Patent Application
20170217166
The present invention relates to a liquid ejection device, a method of manufacturing a liquid ejection device, and a printer.
A liquid ejection device (liquid ejection head) is configured to change liquid pressure in a region filled with liquid (pressure chamber) to eject liquid from a discharge port. A drop-on-demand liquid ejection device is most generally widespread. Further, systems for applying pressure to liquid are broadly divided into two systems. One of the systems is a system in which a capacity of the pressure chamber is changed by applying a drive signal to a piezoelectric element to displace the piezoelectric element, to thereby apply pressure to liquid. The other of the systems is a system in which a resistor produces heat by a drive signal applied to the resistor to generate an air bubble in the pressure chamber, to thereby apply pressure to liquid.
The liquid ejection device using the piezoelectric element can be manufactured relatively easily by mechanically processing a bulk piezoelectric material. Further, the liquid ejection device using the piezoelectric element is also advantageous in that there are few restrictions imposed on a kind of liquid and that liquid containing various materials can be ejected. From such a viewpoint, in recent years, there is an increase in attempts to use the liquid ejection device using the piezoelectric element for an industrial purpose such as manufacture of a color filter or formation of wiring.
Further, a technology involving changing a capacity of a pressure chamber (liquid channel) by displacing a partition formed of a piezoelectric material in a shear mode, to thereby eject liquid, can precisely control the capacity change of the pressure chamber, and thus has attracted great attention (Patent Literature 1).
Further, in recent years, there is a demand to eject a minute liquid droplet. For example, liquid ejection on the order of picoliters is required. Further, liquid ejection even on the order of subpicoliters or smaller is required.
However, it is not necessarily easy to eject a minute liquid droplet with stability.
It is an object of the present invention to provide a liquid ejection device capable of ejecting a minute liquid droplet with stability.
According to one aspect of an embodiment, a liquid ejection device, including: a base including: a first piezoelectric member; and a second piezoelectric member fixed to the first piezoelectric member and polarized in a direction opposite to a polarization direction of the first piezoelectric member; a pressure chamber formed to the base and separated by at least two partitions formed of the first piezoelectric member and the second piezoelectric member; and an electrode formed on each of both side surfaces of the at least two partitions, wherein: the pressure chamber is narrow on a front surface side on which a discharge port configured to eject liquid is formed; a surface of the at least two partitions that faces the pressure chamber includes: a first partition portion formed of only the first piezoelectric member; and a second partition portion formed of the first piezoelectric member and the second piezoelectric member; the pressure chamber is separated by the first partition portion on the front surface side; the pressure chamber is separated by the second partition portion on a back surface side on which a liquid chamber configured to supply the liquid to the pressure chamber is formed; the electrode formed on each of the both side surfaces of the at least two partitions includes a first electrode on the pressure chamber side and a second electrode on a side opposite to the pressure chamber side; and a capacity of the pressure chamber facing the second partition portion increases, and a capacity of the pressure chamber facing the first partition portion decreases, at a time when a voltage is applied so that a potential of the first electrode becomes lower than a potential of the second electrode, compared to a time when a voltage is applied so that the potential of the first electrode becomes the same as the potential of the second electrode.
According to another aspect of the embodiment, a liquid ejection device, including: a base including: a first piezoelectric member; and a second piezoelectric member fixed to the first piezoelectric member and polarized in a direction opposite to a polarization direction of the first piezoelectric member; a pressure chamber formed to the base and separated by at least two partitions formed of the first piezoelectric member and the second piezoelectric member and by a plate mounted on end surfaces of the at least two partitions; and an electrode formed on each of both side surfaces of the at least two partitions, wherein: the pressure chamber is narrow on a front surface side on which a discharge port configured to eject liquid is formed; a surface of the at least two partitions that faces the pressure chamber includes: a first partition portion formed of only the first piezoelectric member; and a second partition portion formed of the first piezoelectric member and the second piezoelectric member; the pressure chamber is separated by the first partition portion on the front surface side; the pressure chamber is separated by the second partition portion on a back surface side on which a liquid chamber configured to supply the liquid to the pressure chamber is formed; and the electrode formed on at least one side surface of the first partition portion is formed within a range other than a predetermined range from the end surface.
According to further another aspect of the embodiment, a method of manufacturing a liquid ejection device, including: forming a groove in a first piezoelectric member and a second piezoelectric member fixed to the first piezoelectric member and polarized in a direction opposite to a polarization direction of the first piezoelectric member, to thereby form a pressure chamber separated by a partition including a first partition portion obtained by cutting up to the first piezoelectric member and a second partition portion obtained by cutting from the first piezoelectric member up to the second piezoelectric member; forming an electrode on the partition; and removing the electrode formed on at least one side surface of the first partition portion and formed within a predetermined range from an end surface of the partition.
According to further another aspect of the embodiment, a printer, including the above mentioned liquid ejection device.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
When a speed of a liquid droplet to be ejected becomes equal to or higher than a given speed, a minute liquid droplet separate from a main droplet (main liquid droplet) is unintentionally generated before the main droplet. Such a minute liquid droplet as to be generated separately from the main droplet is referred to as “satellite droplet”.
In general, in liquid ejection, the liquid is ejected while a liquid ejection device is being moved relatively to a target on which the liquid droplet is to land. Therefore, after a satellite droplet is generated, the satellite droplet lands in a position different from a landed position of the main droplet. The generation of the satellite droplet causes a pattern failure and the like.
Preferred embodiments of the present invention will now be described in detail in accordance with the accompanying drawings.
A liquid ejection device according to an embodiment of the present invention is described with reference to the drawings.
Note that, a case where a piezoelectric plate 12 is positioned on an upper side and a cover plate 11 is positioned on a lower side is illustrated in
As illustrated in
The piezoelectric plate 12 has a substantially flat plate shape. The piezoelectric plate 12 includes a piezoelectric member 12a and a piezoelectric member 12b fixed on the piezoelectric member 12a. More specifically, as illustrated in
As a material of the piezoelectric bodies 12a and 12b, for example, piezoelectric ceramics is used. As the piezoelectric ceramics, for example, a lead zirconate titanate (PZT: PbZrxTi1-xO3)-based ceramics material, which is a ferroelectric ceramics material, is used. Note that, as the piezoelectric ceramics for forming the piezoelectric bodies 12a and 12b, there may be used, for example, barium titanate (BaTiO3), or lanthanum-substituted lead zirconate titanate (PLZT: (Pb,La)(Zr,Ti)O3).
A plurality of grooves (openings) 1 and 2 are formed in the piezoelectric plate 12 so as to be in parallel with one another. A longitudinal direction of the grooves 1 and 2 is matched with a direction indicated by the arrow A of
The piezoelectric plate 12 includes partitions (piezoelectric partitions) 3 defined between the groove 1 and the groove 2. Each of the partitions 3 separates pressure chambers 1 and 2 formed in groove shapes from each other. The longitudinal direction of the partition 3 is matched with the arrow A of
On an end surface of the front surface side of the piezoelectric plate 12, that is, an end surface of the piezoelectric plate 12 on the side to which the orifice plate 60 is mounted, a groove 7 for forming an extracting electrode 23a (see
The cover plate (sometimes referred to simply as “plate”) 11 is mounted to an end surface (here referred to as “principal surface” (surface on the lower side of the drawing sheet of
The pressure chamber 1 and the pressure chamber 2 adjacent to the pressure chamber 1 are separated from each other by the same partition 3. Therefore, it is not necessarily easy to independently control a capacity of the pressure chamber 1 and a capacity of the pressure chamber 2 adjacent to the pressure chamber 1. Therefore, the pressure chamber 1 is used as a liquid channel, and the pressure chamber 2 adjacent to the pressure chamber 1 is used as a dummy.
The respective capacities of the pressure chambers 1 and 2 can also be controlled so that the pressure chamber 2 can also be used as the liquid channel. For example, an electrode 21b (see
Here, a case where the pressure chamber 2 is not used as the liquid channel is described as an example.
As illustrated in
On the other hand, in a region 19 on the back surface side of the piezoelectric transducer 10, the pressure chamber 1 is set to be relatively large (wide) in depth. Specifically, in the region 19 positioned on the other side of the pressure chamber 1 in the longitudinal direction A, the bottom of the pressure chamber 1 is positioned in a position deeper than the boundary between the piezoelectric member 12a and the piezoelectric member 12b. Therefore, in the region 19 on the back surface side of the piezoelectric plate 12, the partition 3 is formed of the piezoelectric member 12a and the piezoelectric member 12b. Specifically, in the region 19 on the back surface side of the piezoelectric plate 12, the partition 3 has a chevron structure. In this embodiment, a portion of a partition formed of the piezoelectric member 12b serving as the first piezoelectric member and the piezoelectric member 12a serving as a second piezoelectric member is referred to as “second partition portion”. Note that, in this specification, for the sake of convenience of description, the same reference numeral “19” is used for the region on the back surface side of the piezoelectric transducer 10 and a region of the back surface side of the piezoelectric plate 12.
As illustrated in
The electrodes (drive electrodes) 21b are formed in the pressure chamber 1. The electrode 21b formed in the pressure chamber 1 is used for applying, in combination with the electrode 21a formed in the dummy chamber 2 to be described later, the partition (piezoelectric member) 3 with an electric field in a direction perpendicular to the polarization direction to displace the partition 3 in a shear mode. The electrodes 21b are formed on the side walls 25 of the partition 3 and a bottom surface of the groove 1.
The electrode 21b is not formed on a wall surface (side surface) 31 positioned in an upper portion (predetermined range from an end surface (surface to be bonded to the cover plate) of the first partition portion) of the partition 3 in the region 18 on the front surface side of the piezoelectric transducer 10, but is formed on a wall surface 30 positioned below the wall surface 31 (range other than the predetermined range) (
On the other hand, in the region 19 on the back surface side of the piezoelectric transducer 10, as illustrated in
The electrode 21a is formed on the side walls 26 of the partition 3 and a bottom surface of the groove 2. The height (height from the bottom surface of the groove 1 to the upper end of the electrode 21a) of the electrode 21a is set, for example, to be the same as the height (height from the bottom surface of the groove 1 to the upper surface of the partition 3) H1 of the partition 3. Note that, the height of the electrode 21a is not limited thereto, and can be set appropriately so as to allow the partition 3 to be sufficiently displaced. The electrode 21a positioned on one side of the dummy chamber 2 and the electrode 21a positioned on the other side of the dummy chamber 2 are separated from each other by a separating groove 20 formed on a bottom surface of the dummy chamber 2. The separating groove 20 is formed along the longitudinal direction (direction indicated by the arrow A) of the dummy chamber 2 so as to extend from one end of the groove 2 and reach the other end of the groove 2. Further, in the groove 7 formed on the front surface side of the piezoelectric plate 12, the separating groove 20 is connected to a separating groove 28 formed on one principal surface (surface on the upper side of the drawing sheet of
The pressure chamber 1 is formed so as to reach the end surface of the piezoelectric plate 12 on the back surface side, that is, the end surface of the piezoelectric plate 12 on the side to which the manifold 40 is mounted (see
On the other hand, the dummy chamber 2 is formed so as not to reach the end surface of the piezoelectric plate 12 on the back surface side, that is, the end surface of the piezoelectric plate 12 on the side to which the manifold 40 is mounted. With this, the liquid is prevented from being supplied from the manifold 40 into the dummy chamber 2.
The manifold 40 is mounted to the back surface side of the piezoelectric transducer 10. A common liquid chamber 43 (see
The orifice plate 60 is mounted on the front surface (surface on a liquid ejecting side) side of the piezoelectric transducer 10. The orifice plate 60 is formed of, for example, plastic. Nozzles (discharge ports) 60a are formed in the orifice plate 60 at positions corresponding to those of the pressure chambers (liquid channels) 1. The nozzles 60a are arrayed in the direction indicated by the arrow B of
As illustrated in
As illustrated in
Next, a method of applying a voltage to the each electrode of the liquid ejection device according to this embodiment is described with reference to
As illustrated in
As illustrated in
As illustrated in
The extracting electrodes 4a1, 4a2, and 4a3 are electrically connected to the respective signal lines 51 formed on the flexible substrate 50 (
Therefore, when a voltage Va is applied to any one of the signal lines 51 formed on the flexible substrate 50 (
Further, in the same manner, when a voltage Vb is applied to any one of the signal lines 51 formed on the flexible substrate 50 (
Next, displacement of the partition of the piezoelectric transducer of the liquid ejection device according to this embodiment is described with reference to
A case where the potential Va of the electrode 21a within the dummy chamber 2 is equal to the potential Vb of the electrode 21b within the pressure chamber 1, that is, a case where Va=Vb, is illustrated in
A case where the potential Va of the electrode 21a within the dummy chamber 2 is higher than the potential Vb of the electrode 21b within the pressure chamber 1, that is, a case where Va>Vb, is illustrated in
As illustrated in
As illustrated in
A case where the potential Va of the electrode 21a within the dummy chamber 2 is lower than the potential Vb of the electrode 21b within the pressure chamber 1, that is, a case where Va<Vb, is illustrated in
As illustrated in
As illustrated in
Next, an operation of the liquid ejection device according to this embodiment is described with reference to
A case where the potential Va of the electrode 21a within the dummy chamber 2 is equal to the potential Vb of the electrode 21b within the pressure chamber 1, that is, a case where Va=Vb, is illustrated in
When the partition 3 is thus displaced, the ink I flows into the partial pressure chamber 1a positioned in the region 19 on the back surface side of the piezoelectric transducer 10. On the other hand, in the partial pressure chamber 1b positioned in the region 18 on the front surface side of the piezoelectric transducer 10, the ink I in the vicinity of the nozzle 60a flows in an ejection direction A1.
In this embodiment, in the case of
Further, it is possible to eject liquid with stability at a desired ejection speed by appropriately setting the displacement amount of the partition 3 in the region 18 on the front surface side of the piezoelectric transducer 10 and the displacement amount of the partition 3 in the region 19 on the back surface side of the piezoelectric transducer 10.
In this way, according to this embodiment, in the region 19 on the back surface side of the piezoelectric transducer 10, the bottom surface of the pressure chamber 1 is positioned in the position deeper than the boundary between the piezoelectric member 12a and the piezoelectric member 12b. On the other hand, in the region 18 on the front surface side of the piezoelectric transducer 10, the bottom surface of the pressure chamber 1 is positioned in the position shallower than the boundary between the piezoelectric member 12a and the piezoelectric member 12b. Further, on the front surface side of the piezoelectric transducer 10, the upper end of the first electrode 21b is positioned below the upper surface of the partition 3. Therefore, according to this embodiment, the partition 3 can be displaced in the region 18 on the front surface side of the piezoelectric transducer 10. Accordingly, when the pressure chamber 1 is contracted in the region 19 on the back surface side of the piezoelectric transducer 10, the pressure chamber 1 is expanded in the region 18 on the front surface side of the piezoelectric transducer 10. Therefore, according to this embodiment, when the liquid droplet is ejected by contracting the region 19 on the back surface side of the piezoelectric transducer 10, it is possible to alleviate the sudden concentration of pressure into a nozzle, which can inhibit a satellite droplet from being generated. Accordingly, according to this embodiment, it is possible to provide a liquid ejection device capable of ejecting a minute liquid droplet with stability.
Next, a method of manufacturing a liquid ejection device according to this embodiment is described with reference to
First, two piezoelectric substrates (piezoelectric bodies) 12a and 12b having opposite polarization directions are bonded together by use of the adhesive layer 16 (see
Subsequently, a surface of the piezoelectric member 12b is subjected to cutting (grinding) so that the thickness of the piezoelectric member 12b becomes a desired thickness. In this way, the piezoelectric plate 12 in which the piezoelectric member 12b having a desired thickness is arranged on the piezoelectric member 12a is obtained (see
Subsequently, as illustrated in
Specifically, the plurality of grooves 1 are formed so as to be in parallel with one another. In the forming of the grooves 1, only the piezoelectric member 12b is processed in the region 18 in the vicinity of the end surface of the piezoelectric plate 12 on the front surface side (front side of the drawing sheet of
Then, the grooves 2 for forming the dummy chambers are formed in the piezoelectric plate 12 by use of the diamond blade (not shown). As a dicing apparatus, for example, a dicing apparatus similar to the dicing apparatus used in forming the grooves 1 can be used. The grooves 2 are formed so as to be along the longitudinal direction of the grooves 1. The plurality of grooves 2 are formed so as to be in parallel with one another. Regions in which the grooves 2 are to be formed are set so that the plurality of grooves 2 are at the centers between the plurality of grooves 1 formed so as to be in parallel with one another, respectively. The grooves 2 are formed so as not to reach the end surface of the piezoelectric plate 12 on the back surface side. This is for the purpose of preventing liquid from being supplied from the manifold 40 into the dummy chambers 2. In the region 19 on the back surface side of the piezoelectric plate 12, the depth of the grooves 2 is, for example, the same as that of the grooves 1. Note that, the depth of the grooves 2 is not required to be the same as that of the grooves 1. For example, the depth of the grooves 2 may be appropriately set in a range of from 1 to 1.15 times as much as the depth of the grooves 1. A portion between the groove 1 and the groove 2 serves as the partition 3. The partition 3 is positioned on both sides of the pressure chamber formed by the groove 1.
Then, the grooves 7 are formed in the end surface of the piezoelectric plate 12 on the front surface side by use of the diamond blade (not shown). The grooves 7 are formed so as to extend in the direction of the normal to the principal surface of the piezoelectric plate 12. The grooves 7 are formed for the purpose of forming the extracting electrodes 23a extracted from the electrodes 21a. Processing conditions in forming the grooves 7 are, for example, similar to processing conditions in forming the grooves 2. The grooves 7 are formed on the front surface side of the piezoelectric plate 12, that is, on the front side of the drawing sheet of
Note that, the case of the processing using the diamond blade is described here as an example, but the present invention is not limited thereto.
A processing tool capable of performing the processing so as to keep the piezoelectric plate 12 below a Curie temperature can be appropriately used. For example, the piezoelectric plate 12 may be processed by use of an end mill or the like.
Then, as illustrated in
First, by etching the surface of the piezoelectric plate 12, minute depressions (unevenness) are formed in the surface of the piezoelectric plate 12. Then, de-leading treatment for removing from the surface of the piezoelectric plate 12 lead (Pb) contained in the material of the piezoelectric plate 12 is applied.
Next, as described below, a plated catalyst is deposited onto the surface of the piezoelectric plate 12. For example, tin (Sn) and palladium (Pd) are used as the plated catalyst. In this case, the deposition is described by way of the case where the plated catalyst of palladium is generated. First, the piezoelectric plate 12 is immersed into an aqueous solution of stannous chloride with a concentration of about 0.1%, thereby depositing stannous chloride onto the surface of the piezoelectric plate 12. Subsequently, the piezoelectric plate 12 is immersed into an aqueous solution of palladium chloride with a concentration of about 0.1%, thereby allowing an oxidation-reduction reaction between tin chloride, which is deposited onto the piezoelectric plate 12 in advance, and palladium chloride to occur to generate metallic palladium on the surface of the piezoelectric plate 12. Thus, the plated catalyst of metallic palladium is deposited onto the surface of the piezoelectric plate 12.
Next, the piezoelectric plate 12 in which metallic palladium is generated on its surface is immersed into, for example, a nickel plating bath, thereby forming an electroless plating film containing nickel (Ni) on the surface of the piezoelectric plate 12. For example, the following films are formed as the electroless plating film: an electroless plating film of nickel-phosphorus (Ni—P) and an electroless plating film of nickel-boron (Ni—B). It is preferred that a thickness of the electroless plating film be set to be about 0.5 μm to 1.0 μm for the purpose of sufficiently cover the surface of the piezoelectric plate 12 and sufficiently reducing electrical resistance. In this way, the electroless plating film is formed on the entire surface of the piezoelectric plate 12.
After that, for example, through replacement plating, a gold (Au) plating film, for example, is formed on the electroless plating film. In this way, the conductive film 55 including the plating film is formed on the entire surface of the piezoelectric plate 12.
Then, unnecessary portions of the conductive film 55 formed on the entire surface of the piezoelectric plate 12 are removed (see
Portions of the conductive film 55 on one principal surface (surface on the upper side of the drawing sheet of
Further, the separating groove 20 is formed at the bottom of the groove 2 to serve as the dummy chamber, and the separating groove 28 is formed at the bottom of the groove 7 for the extracting electrode. Those separating grooves 20 and 28 are for the purpose of separating the electrode 21a positioned on one side of the grooves 2 and 7 and the electrode 21a positioned on the other side of the grooves 2 and 7 from each other. When the separating grooves 20 and 28 are formed, for example, the diamond blade can be used. The separating grooves 20 and 28 each have a width of, for example, about ½ to ⅓ of the width of the groove 2 or 7. Note that, the width of the separating grooves 20 and 28 is not limited thereto, and may be appropriately set. The separating groove 20 is formed along the longitudinal direction of the groove 2 so as to extend from a front end of the groove 2 to reach a rear end thereof. Further, the separating groove 28 is formed along the longitudinal direction of the groove 7 so as to extend from an upper end of the groove 7 to reach a lower end thereof. The electrode 21a positioned on one side of the groove 2 or 7 and the electrode 21a positioned on the other side of the groove 2 or 7 are separated from each other, and thus, different signal voltages can be applied to those electrodes 21a. Therefore, the partitions 3 of the pressure chambers 1 can be individually displaced.
Subsequently, as illustrated in
Note that, it is also possible to remove an unnecessary portion of the conductive film 55 existing on the side wall 25 of the partition 3 by using a laser beam or the like. As the laser beam, for example, an excimer laser or a KrF laser is used. The laser beam has an energy density of, for example, about 1 J/cm2 to 10 J/cm2. Through scanning with the laser beam at an appropriate speed, the unnecessary portion of the conductive film 55 can be removed.
In this way, the unnecessary portion of the conductive film formed on the surface of the piezoelectric plate 12 is removed to form the electrode 21a in a desired shape.
Then, as illustrated in
Subsequently, the front surface side, the back surface side, and the like of the piezoelectric plate 12 are subjected to grinding, polishing, and the like, to thereby remove the conductive film 55 from the piezoelectric plate 12 and adjust the external shape and dimensions.
Subsequently, the separating groove (not shown) 28 is appropriately formed in one principal surface (surface on the upper side of the drawing sheet of
After that, the manifold 40 is mounted on the back surface side of the piezoelectric transducer 10 (see
Further, the orifice plate 60 is mounted on the front surface side of the piezoelectric plate 12 (see
Further, the flexible substrate 50 is mounted to one principal surface (surface on the upper side of the drawing sheet of
In this way, the liquid ejection device according to this embodiment is manufactured.
Next, a liquid ejection device according to Modification Example (Part 1) of this embodiment is described with reference to
In the liquid ejection device according to this modification example, in the region 18 on the front surface side of the piezoelectric transducer 10, the upper end of the electrode 21a is positioned below the upper surface of the partition 3.
As illustrated in
The electrode 21b is formed on the side wall 25 of the partition 3 and the bottom surface of the groove 1. The height (height from the bottom surface of the groove 1 to the upper end of the electrode 21b) of the electrode 21b is set, for example, to be the same as the height (height from the bottom surface of the groove 1 to the upper surface of the partition 3) H1 of the partition 3. Specifically, in this modification example, the upper end of the electrode 21b is not positioned below the upper surface of the partition 3.
In the region 19 on the back surface side of the piezoelectric transducer 10, this modification example has the same structure as the structure described above with reference to
In this way, in the region 18 on the front surface side of the piezoelectric transducer 10, the upper end of the electrode 21a may be positioned below the upper surface of the partition 3. Also in this modification example, in the same manner as in the liquid ejection device according to the embodiment, the partition 3 can be displaced in the region 18 on the front surface side of the piezoelectric transducer 10.
Next, a method of manufacturing a liquid ejection device according to this modification example is described with reference to
A step of forming the piezoelectric plate 12 to a step of forming the separating grooves 20 and 28 are the same as those of the method of manufacturing a liquid ejection device described above with reference to
Subsequently, as illustrated in
The subsequent steps of the method of manufacturing a liquid ejection device are the same as those of the method of manufacturing a liquid ejection device according to the embodiment described above, and hence descriptions thereof are omitted.
In this way, the liquid ejection device according to this modification example is manufactured.
Next, a liquid ejection device according to Modification Example (Part 2) of this embodiment is described with reference to
In the liquid ejection device according to this modification example, in the region 18 on the front surface side of the piezoelectric transducer 10, the upper end of the electrode 21b is positioned below the upper surface of the partition 3, and the upper end of the electrode 21a is also positioned below the upper surface of the partition 3.
As illustrated in
In the region 18 on the front surface side of the piezoelectric transducer 10, the electrode 21a is not formed on the wall surface 33 positioned in the upper portion of the partition 3, and the electrode 21a is formed on the wall surface 32 positioned below the wall surface 33. In the region 18 on the front surface side of the piezoelectric transducer 10, the height (height from the bottom surface of the groove 1 to the upper end of the electrode 21a) H6 of the electrode 21a is set to, for example, about half as much as the height (height from the bottom surface of the groove 1 to the upper surface of the partition 3) H1 of the partition 3. Note that, the height H6 of the electrode 21a is not limited thereto, and can be set appropriately so as to allow the partition 3 to be sufficiently displaced.
In the region 19 on the back surface side of the piezoelectric transducer 10, this modification example has the same structure as the structure described above with reference to
In this way, in the region 18 on the front surface side of the piezoelectric transducer 10, the upper end of the electrode 21b is positioned below the upper surface of the partition 3, and the upper end of the electrode 21a may also be positioned below the upper surface of the partition 3. Also in this modification example, in the same manner as in the liquid ejection device according to the embodiment, the partition 3 can be displaced in the region 18 on the front surface side of the piezoelectric transducer 10.
Next, a method of manufacturing a liquid ejection device according to this modification example is described with reference to
A step of forming the piezoelectric plate 12 to a step of forming the separating grooves 20 and 28 are the same as those of the method of manufacturing a liquid ejection device described above with reference to
Subsequently, as illustrated in
The subsequent steps of the method of manufacturing a liquid ejection device are the same as those of the method of manufacturing a liquid ejection device according to the embodiment described above, and hence descriptions thereof are omitted.
Next, a liquid ejection device according to Modification Example (Part 3) of this embodiment is described with reference to
In the liquid ejection device according to this modification example, in the region 18 on the front surface side of the piezoelectric transducer 10, the thickness of the partition 3 in the upper portion is set to be smaller than the thickness of the partition 3 in the lower portion.
As illustrated in
The electrode 21b is formed on the wall surface 34, but is not formed on the wall surface 35. The height of the upper end of the electrode 21b is set to be the same as the height of an upper end of the wall surface 34.
In other words, a wall surface (side surface) positioned in the upper portion (predetermined range from the end surface (surface to be bonded to the cover plate) of the first partition portion) of the partition 3 in the region 18 on the front surface side of the piezoelectric transducer 10 is set to be smaller in thickness than a partition portion within a range other than the predetermined range.
The first partition portion within the predetermined range, which is only a little thinner than the first partition portion within a range other than the predetermined range, is effective. It is preferred that the thickness of the first partition portion within the predetermined range be as small as 45% or more and 99% or less of the thickness of the first partition portion within the range other than the predetermined range because a strength of the first partition portion is adversely affected with a thickness less than 45%.
In the region 19 on the back surface side of the piezoelectric transducer 10, this modification example has the same structure as the structure described above with reference to
In this way, in the region 18 on the front surface side of the piezoelectric transducer 10, the wall surface 35 positioned in the upper portion of the side wall 25 of the partition 3 may be recessed with respect to the wall surface 34 positioned below the wall surface 35 in the direction of the normal to the wall surface 35. Also in this modification example, in the same manner as in the liquid ejection device according to the embodiment, the partition 3 can be displaced in the region 18 on the front surface side of the piezoelectric transducer 10.
Next, a method of manufacturing a liquid ejection device according to this modification example is described with reference to
A step of forming the piezoelectric plate 12 to a step of forming the separating grooves 20 and 28 are the same as those of the method of manufacturing a liquid ejection device described above with reference to
Subsequently, as illustrated in
The subsequent steps of the method of manufacturing a liquid ejection device are the same as those of the method of manufacturing a liquid ejection device according to the embodiment described above, and hence descriptions thereof are omitted.
Next, a liquid ejection device according to Modification Example (Part 4) of this embodiment is described with reference to
In the liquid ejection device according to this modification example, as illustrated in
The electrode 21a is formed on the wall surface 37, but is not formed on the wall surface 38. The height of the upper end of the electrode 21a is set to be the same as the height of an upper end of the wall surface 37.
In the region 19 on the back surface side of the piezoelectric transducer 10, this modification example has the same structure as the structure described above with reference to
In this way, in the region 18 on the front surface side of the piezoelectric transducer 10, the wall surface 38 positioned in the upper portion of the partition 3 may be recessed with respect to the wall surface 37 positioned below the wall surface 38 in the direction of the normal to the wall surface 38. Also in this modification example, in the same manner as in the liquid ejection device according to the embodiment, the partition 3 can be displaced in the region 18 on the front surface side of the piezoelectric transducer 10.
Next, a method of manufacturing a liquid ejection device according to this modification example is described with reference to
A step of forming the piezoelectric plate 12 to a step of forming the separating grooves 20 and 28 are the same as those of the method of manufacturing a liquid ejection device described above with reference to
Subsequently, as illustrated in
The subsequent steps of the method of manufacturing a liquid ejection device are the same as those of the method of manufacturing a liquid ejection device according to the embodiment described above, and hence descriptions thereof are omitted.
Next, a liquid ejection device according to Modification Example (Part 5) of this embodiment is described with reference to
In the liquid ejection device according to this modification example, in the region 18 on the front surface side of the piezoelectric transducer 10, the wall surfaces 35 and 38 positioned in the upper portions of the side walls 25 and 26 of the partition 3 are recessed with respect to the wall surfaces 34 and 37 positioned below the wall surfaces 35 and 38 in the normal directions of the wall surfaces 35 and 38, respectively. Therefore, in this modification example, the thickness of the partition 3 in the upper portion is sufficiently smaller than the thickness of the partition 3 in the lower portion. Here, for the sake of convenience of description, the description is made on the assumption that the lower side of the drawing sheets of
The electrode 21b is formed on the wall surface 34, but is not formed on the wall surface 35. The height of the upper end of the electrode 21b is set to be the same as the height of the upper end of the wall surface 34. The electrode 21a is formed on the wall surface 37, but is not formed on the wall surface 38. The height of the upper end of the electrode 21a is set to be the same as the height of the upper end of the wall surface 37.
In the region 19 on the back surface side of the piezoelectric transducer 10, this modification example has the same structure as the structure described above with reference to
In this way, in the region 18 on the front surface side of the piezoelectric transducer 10, the wall surfaces 35 and 38 positioned in the upper portions of the side walls 25 and 26 of the partition 3 may be recessed with respect to the wall surfaces 34 and 37 positioned below the wall surfaces 35 and 38 in the direction of the normal to the wall surfaces 35 and 38, respectively. Also in this modification example, in the same manner as in the liquid ejection device according to the embodiment, the partition 3 can be displaced in the region 18 on the front surface side of the piezoelectric transducer 10.
Next, a method of manufacturing a liquid ejection device according to this modification example is described with reference to
A step of forming the piezoelectric plate 12 to a step of forming the separating grooves 20 and 28 are the same as those of the method of manufacturing a liquid ejection device described above with reference to
Subsequently, as illustrated in
The subsequent steps of the method of manufacturing a liquid ejection device are the same as those of the method of manufacturing a liquid ejection device according to the embodiment described above, and hence descriptions thereof are omitted.
Note that, the present invention is not limited to the above-mentioned embodiment. Changes can be made thereto appropriately by a person who has common knowledge in this technical field within the scope that does not depart from the technical thought of the present invention.
Further, in the above-mentioned embodiment, the inkjet head to be used for a printer or the like is described as an example of the liquid ejection device, but the present invention is not limited thereto. For example, the liquid ejection device may be a liquid ejection device configured to eject liquid containing metal fine particles. When the liquid containing metal fine particles is ejected, it is possible to form metal wiring (metal pattern) or the like. Further, the liquid ejection device may be a liquid ejection device configured to eject resist liquid (resist ink). When the resist liquid is ejected, it is possible to form a resist pattern.
Next, more specific examples of the present invention are described.
First, Example 1 is described with reference to
In Example 1, the groove 1 was formed by being subjected to processing using the diamond blade. Therefore, in Example 1, the pressure chamber 1 was set to partially have a tapered shape. In Example 1, a flat portion 61 that is a part having a flat bottom surface of the pressure chamber 1 was formed in the region 18 on the front surface side (left side of the drawing sheet of
In Example 1, a dimension L of the pressure chamber 1 in the longitudinal direction, that is, a length L of the pressure chamber 1 was set to 8 mm. Further, in Example 1, a length L1 of the flat portion 61 in the region 18 on the front surface side of the piezoelectric transducer 10 was set to 0.5 mm. Further, in Example 1, a length L2 of the partial tapered portion 62 in the region 18 on the front surface side of the piezoelectric transducer 10 was set to 1.1 mm. Further, in Example 1, a length L3 of the partial tapered portion 63 in the region 19 on the back surface side of the piezoelectric transducer 10 was set to 2.8 mm. Further, in Example 1, a length L4 of the flat portion 64 in the region 19 on the back surface side of the piezoelectric transducer 10 was set to 3.6 mm.
The direction indicated by the arrow C of
Further, in Example 1, a dimension W1 of the partition 3 in a direction indicated by an arrow B of
In Example 1, as illustrated in
Specifically, in Example 1, the upper end of the electrode 21a formed on the one side wall 26 of the partition 3 was made to be matched in level with the upper surface of the partition 3.
On the other hand, in Example 1, the upper end of the electrode 21b formed on the other side wall 25 of the partition 3 was recessed downward from the upper surface of the partition 3. In the flat portion 61, the upper portion of the electrode 21b was removed by a height D1. The height D1 by which the electrode 21b was removed, that is, the dimension D1 between the upper surface of the partition 3 and the upper end of the electrode 21b was set to 50 μm that is half as much as the height H1 from the bottom surface of the pressure chamber 1 to the upper surface of the partition 3 in the flat portion 61. In the tapered portion 62, the upper portion of the electrode 21b was removed by an increasing height. At a boundary 67 between the region 18 on the front surface side and the region 19 on the back surface side of the piezoelectric transducer 10, a height D2 by which the upper portion of the electrode 21b is removed was set to 75 μm that is half as much as a height H3 of the piezoelectric member 12b. The upper portion of the electrode 21b was removed by use of the laser beam.
After that, the cover plate 11 was mounted to the piezoelectric plate 12 processed in this manner, and then the manifold 40, the orifice plate 60, the flexible substrate 50, and the like were mounted to the piezoelectric transducer 10, to obtain the liquid ejection device according to Example 1.
The liquid ejection device according to Example 1 was caused to eject liquid to be evaluated. As the liquid to be ejected in the evaluation, an ethylene glycol solution diluted with water was used. A concentration of ethylene glycol within the liquid was set to 80 wt %. When the liquid is ejected from the liquid ejection device according to Example 1, voltages to be applied to the electrodes 21a and 21b were set as follows.
That is, the electrode 21b was set to have a potential of 0 V. On the other hand, a pulse-like signal having a positive voltage was applied to the electrode 21a. The signal to be applied to the electrode 21a was set to have a pulse width of 8 μs.
An image pickup apparatus to which a microscope was mounted was used to take an image of a liquid droplet in a flying state. As a light source used for taking the image of the liquid droplet in the flying state, a light source configured to emit nano-pulse laser light was used.
As the voltage of the pulse-like signal to be applied to the electrode 21a was increased, the speed of the liquid droplet increased. When the speed of the liquid droplet (main droplet) became equal to or more than a given speed, a minute liquid droplet (satellite droplet) separate from the main droplet was generated before the main droplet. The speed of the main droplet exhibited when the satellite droplet began to be generated differed depending on the diameters of the nozzles 60a. The speed of the main droplet exhibited when the satellite droplet began to be generated is shown in Table 1.
In Comparative Example, the liquid ejection device from which the upper portion of the electrode 21b was not removed was evaluated.
As can be seen from Table 1, in Comparative Example, when the diameter of the nozzle 60a was set to be relatively small, the satellite droplet was generated even with a relatively low speed of the liquid droplet.
In contrast, in Example 1, even when the diameter of the nozzle 60a was relatively small and when the speed of the liquid droplet was relatively high, the satellite droplet was hardly generated.
In Comparative Example, it is conceivable that, when the diameter of the nozzle 60a is set to be relatively small, the satellite droplet is generated even when the speed of the liquid droplet is relatively low for the following reason. Specifically, in Comparative Example, in the region 18 on the front surface side of the piezoelectric transducer 10, the upper portions of the electrodes 21a and 21b are not removed. In addition, the upper surface of the partition 3 is fixed to the cover plate 11. Therefore, in Comparative Example, in the region 18 on the front surface side of the piezoelectric transducer 10, the partition 3 is not displaced. Therefore, in Comparative Example, when the partial pressure chamber 1a (see
In Example 1, the upper portion of the electrode 21b is removed in the region 18 on the front surface side of the piezoelectric transducer 10, and hence the partition 3 can be displaced in the region 18 on the front surface side of the piezoelectric transducer 10. In Example 1, when the partial pressure chamber 1a is contracted, the partial pressure chamber 1b is expanded. Therefore, according to Example 1, it is possible to alleviate the concentration of the pressure of the liquid into the nozzle 60a. Therefore, according to Example 1, even when the diameter of the nozzle 60a is relatively small and when the speed of the liquid droplet is relatively high, it is possible to prevent the satellite droplet from being easily generated.
Next, Example 2 is described with reference to
Example 2 corresponds to the liquid ejection device according to Modification Example (Part 1) described above with reference to
In Example 2, as illustrated in
Specifically, in Example 2, the upper end of the electrode 21b formed on the one side wall 25 of the partition 3 was made to be matched in level with the upper surface of the partition 3.
On the other hand, in Example 2, the upper end of the electrode 21a formed on the other side wall 26 of the partition 3 was positioned below the upper surface of the partition 3. In the flat portion 61, the upper portion of the electrode 21a was removed by the height D1. The height D1 by which the electrode 21a was removed, that is, the dimension D1 between the upper surface of the partition 3 and the upper end of the electrode 21a was set to 50 μm that is half as much as the height H1 from the bottom surface of the pressure chamber 1 to the upper surface of the partition 3 in the flat portion 61. In the tapered portion 62, the upper portion of the electrode 21a was removed by an increasing height. At the boundary 67 between the region 18 on the front surface side and the region 19 on the back surface side of the piezoelectric transducer 10, the height D2 by which the upper portion of the electrode 21a is removed was set to 75 μm that is half as much as the height H3 of the piezoelectric member 12b. The upper portion of the electrode 21a was removed by use of the laser beam.
The thus-obtained liquid ejection device according to Example 2 was evaluated in the same manner as in Example 1. The results of evaluation of the liquid ejection device according to Example 2 are shown in Table 2.
As can be seen from a comparison between Table 1 and Table 2, also in Example 2, substantially the same performance as in Example 1 is obtained.
It is conceivable that the results of evaluation of Example 2 is substantially the same as the results of evaluation of Example 1 because a portion in which the upper portion of the electrode is removed is only changed from the side wall 25 side to the side wall 26 side without any change made to the displacement amount of the partition 3 itself.
Next, Example 3 is described with reference to
Example 3 corresponds to the liquid ejection device according to Modification Example (Part 2) described above with reference to
In Example 3, as illustrated in
Specifically, in Example 3, the upper ends of the electrodes 21a and 21b formed on the respective side walls 25 and 26 of the partition 3 were positioned below the upper surface of the partition 3. In the flat portion 61, the upper portions of the electrodes 21a and 21b were removed by the height D1. The height D1 by which the electrodes 21a and 21b were removed, that is, the dimension D1 between the upper surface of the partition 3 and each of the upper ends of the electrodes 21a and 21b was set to 50 μm that is half as much as the height H1 from the bottom surface of the pressure chamber 1 to the upper surface of the partition 3 in the flat portion 61. In the tapered portion 62, the upper portions of the electrodes 21a and 21b were removed by an increasing height. At the boundary 67 between the region 18 on the front surface side of the piezoelectric transducer 10 and the region 19 on the back surface side, the height D2 by which the upper portions of the electrodes 21a and 21b are removed was set to 75 μm that is half as much as the height H3 of the piezoelectric member 12b. The upper portions of the electrodes 21a and 21b were removed by use of the laser beam.
The thus-obtained liquid ejection device according to Example 3 was evaluated in the same manner as in Examples 1 and 2. The results of evaluation of the liquid ejection device according to Example 3 are shown in Table 3.
As can be seen from comparisons between Table 3 and Tables 1 and 2, the speed of the main droplet exhibited when the satellite droplet began to be generated dropped in Example 3 compared to Examples 1 and 2.
It is conceivable that the speed of the main droplet exhibited when the satellite droplet began to be generated dropped in Example 3 because the displacement amount of the partition 3 in the region 18 on the front surface side of the piezoelectric transducer 10 was smaller in Example 3 than in Examples 1 and 2. The displacement amount of the partition 3 in the region 18 on the principal surface side of the piezoelectric transducer 10 reduces in Example 3 because the electric field applied to the partition 3 decreases when both the upper portions of the electrodes 21a and 21b are removed.
When the displacement amount of the partition 3 in the region 18 on the front surface side of the piezoelectric transducer 10 reduces, an expansion amount of the partial pressure chamber 1b exhibited when the partial pressure chamber 1a is contracted reduces. Therefore, in Example 3, the effect of alleviating the concentration of the pressure of the liquid into the nozzle 60a deteriorates. Therefore, it is conceivable that the speed of the main droplet exhibited when the satellite droplet began to be generated dropped in Example 3 compared to Examples 1 and 2.
Next, Example 4 is described with reference to
Example 4 corresponds to the liquid ejection device according to Modification Example (Part 3) described above with reference to
In Example 4, as illustrated in
Specifically, in Example 4, the upper end of the electrode 21a formed on the one side wall 26 of the partition 3 was made to be matched in level with the upper surface of the partition 3.
On the other hand, in Example 4, the upper portion of the partition 3 was removed on the other side wall 25 side of the partition 3. This caused the wall surface 35 positioned in the upper portion of the side wall 25 (see
In the flat portion 61, the upper portion of the partition 3 on the side wall 25 side was removed by the height D1. The dimension D1 was set to 50 μm that is half as much as the height H1 from the bottom surface of the pressure chamber 1 to the upper surface of the partition 3 in the flat portion 61. In the tapered portion 62, the height by which the upper portion of the electrode 21b is removed was gradually increased. At the boundary 67 between the region 18 on the front surface side and the region 19 on the back surface side of the piezoelectric transducer 10, the height D2 by which the upper portion of the partition 3 was removed on the side wall 25 side was set to 75 μm that is half as much as the height H3 of the piezoelectric member 12b. The upper portion of the partition 3 was removed on the side wall 25 side by use of the end mill.
The thus-obtained liquid ejection device according to Example 4 was evaluated in the same manner as in Example 1. The results of evaluation of the liquid ejection device according to Example 4 are shown in Table 4.
As can be seen from Table 4, the speed of the main droplet exhibited when the satellite droplet began to be generated improved in Example 4 compared to Examples 1 and 2.
It is conceivable that the speed of the main droplet exhibited when the satellite droplet began to be generated improved in Example 4 because the displacement amount of the partition 3 in the region 18 on the front surface side of the piezoelectric transducer 10 was larger in Example 4 than in Examples 1 and 2. It is conceivable that the displacement amount of the partition 3 in the region 18 on the principal surface side of the piezoelectric transducer 10 increases in Example 4 because the rigidity of the partition 3 reduces with a smaller thickness of the partition 3 in the upper portion and the displacement amount of the partition 3 increases.
When the displacement amount of the partition 3 in the region 18 on the front surface side of the piezoelectric transducer 10 increases, an expansion amount of the partial pressure chamber 1b exhibited when the partial pressure chamber 1a is contracted increases. Therefore, in Example 4, the effect of alleviating the concentration of the pressure of the liquid into the nozzle 60a improves. Therefore, it is conceivable that the speed of the main droplet exhibited when the satellite droplet began to be generated improved in Example 4 compared to Examples 1 and 2.
Next, Example 5 is described with reference to
Example 5 corresponds to the liquid ejection device according to the embodiment described above with reference to
In Example 5, a ratio (D1/H1) of the height D1 by which the upper portion of the electrode 21b was removed to the height H1 from the bottom surface of the pressure chamber 1 in the region 18 on the front surface side of the piezoelectric transducer 10 to the upper surface of the partition 3 was changed from 0.2 to 0.8.
Further, in Example 5, a ratio (D2/H3) of the height D2 by which the upper portion of the electrode 21b was removed to the height H3 of the piezoelectric member 12b at the boundary 67 between the region 18 on the front surface side and the region 19 on the back surface side of the piezoelectric transducer 10 was changed from 0.2 to 0.8.
The thus-obtained liquid ejection device according to Example 5 was evaluated in the same manner as in Example 1. The results of evaluation of the liquid ejection device according to Example 5 are shown in Table 5.
As can be seen from Table 5, when the heights D1 and D2 by which the upper portion of the electrode 21b is removed are excessively large or small, the speed of the main droplet exhibited when the satellite droplet begins to be generated drops.
It is conceivable that the speed of the main droplet exhibited when the satellite droplet begins to be generated drops when the heights D1 and D2 by which the upper portion of the electrode 21b is removed are excessively large, because the electric field applied to the partition 3 decreases when the heights D1 and D2 by which the upper portion of the electrode 21b is removed is set to be excessively high, to thereby decrease the displacement amount of the partition 3.
On the other hand, it is conceivable that the speed of the main droplet exhibited when the satellite droplet begins to be generated drops when the heights D1 and D2 by which the upper portion of the electrode 21b is removed are excessively small, because the electric field is also applied to the upper portion of the partition 3 in the same direction as the electric field applied to the lower portion of the partition 3, to thereby decrease the displacement amount of the partition 3.
As can be seen from Table 5, it is preferred that the heights D1 and D2 by which the upper portion of the electrode 21b is removed be 35% or more and 75% or less of the heights H1 and H3 of the partition 3. Specifically, it is preferred that the height from the bottom of the pressure chamber 1 in the region 18 on the front surface side of the piezoelectric transducer 10 to the upper end of the electrode 21b be 25% or more and 65% or less of the height from the bottom of the pressure chamber 1 in the region 18 on the front surface side of the piezoelectric transducer to the upper surface of the partition 3.
Next, Example 6 is described with reference to
Example 6 corresponds to the liquid ejection device according to Modification Example (Part 3) described above with reference to
In Example 6, the thickness W1 of the partition 3 in the lower portion of the partition 3 was set to 60 μm. In Example 6, a ratio (W3/W1) of the recess amount W3 of the wall surface 35 to the thickness W1 of the partition 3 in the lower portion of the partition 3 was changed from 0.16 to 0.66. In Example 6, the diameter of the nozzle 60a was set to φ10 μm.
The thus-obtained liquid ejection device according to Example 6 was evaluated in the same manner as in Example 1. The results of evaluation of the liquid ejection device according to Example 6 are shown in Table 6.
As can be seen from Table 6, the speed of the main droplet exhibited when the satellite droplet begins to be generated improves as the recess amount W3 of the wall surface 35 with respect to the wall surface 34 is set to be larger.
It is conceivable that the speed of the main droplet exhibited when the satellite droplet begins to be generated improves as the recess amount W3 of the wall surface 35 with respect to the wall surface 34 is set to be larger because, as the recess amount W3 of the wall surface 35 with respect to the wall surface 34 is set to be larger, the rigidity of the partition 3 reduces and the displacement amount of the partition 3 increases.
On the other hand, when the recess amount W3 of the wall surface 35 with respect to the wall surface 34 is set to be too large, such a failure that the partition 3 breaks at a process time occurs frequently.
In view of the foregoing, it is preferred that the ratio (W3/W1) of the recess amount W3 of the wall surface 35 to the thickness W1 of the partition 3 in the lower portion of the partition 3 be less than 55%. In other words, it is preferred that the thickness between the wall surface 35 and the side wall 26 in the region 18 on the front surface side of the piezoelectric transducer 10 be 45% or more of the thickness between the wall surface 34 and the side wall 26 in the region 18 on the front surface side of the piezoelectric transducer 10.
According to the present invention, in the region on the back surface side of the piezoelectric transducer, the bottom surface of the pressure chamber is positioned in the position deeper than the boundary between the first piezoelectric member and the second piezoelectric member. On the other hand, in the region on the front surface side of the piezoelectric transducer, the bottom surface of the pressure chamber is positioned in the position shallower than the boundary between the first piezoelectric member and the second piezoelectric member. Then, on the front surface side of the piezoelectric transducer, the upper end of the first electrode is positioned below the upper surface of the partition. Therefore, according to the present invention, in the region on the front surface side of the piezoelectric transducer, the partition can be displaced. Accordingly, when the pressure chamber is contracted in the region on the back surface side of the piezoelectric transducer, the pressure chamber is expanded in the region of the front surface side of the piezoelectric transducer. Therefore, according to the present invention, when the liquid droplet is ejected by contracting the region on the back surface side of the piezoelectric transducer, it is possible to alleviate the sudden concentration of pressure into the nozzle, which can inhibit the satellite droplet from being generated. Accordingly, according to the present invention, it is possible to provide a liquid ejection device that can eject a minute liquid droplet with stability.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2014-184808, filed Sep. 11, 2014 which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-184808 | Sep 2014 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2015/004553 | 9/8/2015 | WO | 00 |
