JP2009292003A - Liquid droplet delivering head, inkjet printer, method for manufacturing liquid droplet delivering head, and method for manufacturing inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid droplet delivering head can improve the amount of displacement. <P>SOLUTION: A piezoelectric body film (17) for a liquid droplet delivering head is arranged approximately at the central part of a first direction of a cavity (Ca), and the width (Wp1) in the first direction of the piezoelectric film is smaller than the width (Wc1) in the first direction of the cavity. There exists a first region (arm part 20) which is a cavity forming region and is not a forming region of the piezoelectric film on both sides in the first direction of the piezoelectric film. A lower electrode (15) includes an opening part (OA1) arranged in the first region and a bridge part (BA) alternately arranged with the opening part. By such a constitution as this, a constitution in which the forming region of the piezoelectric film and the cavity forming region do not overlap each other with the lower electrode in the first region extracted, can be obtained to be able to improve the amount of displacement. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a droplet discharge head, an inkjet printer, a method for manufacturing a droplet discharge head, and a method for manufacturing an inkjet printer.

  An ink jet head, which is an example of a droplet discharge head, is a member that pressurizes a cavity (pressure chamber) with a piezoelectric element and discharges ink (discharge liquid) from the nozzle hole at the bottom of the cavity. Such an ink-jet head is used in an ink-jet printer or the like, and is printed with ink ejected from nozzle holes.

For example, as an inkjet head having the above-described configuration, for example, in Patent Document 1 below, a lower electrode is formed in a region corresponding to the pressure generation chamber 12 via a vibration plate constituting a part of the pressure generation chamber 12 communicating with a nozzle opening. 60, an inkjet head having a piezoelectric layer 70 and an upper electrode 80 is described (see FIG. 7).
JP 2000-246888 A

  The inventor has conducted research and development on a droplet discharge head, particularly a head portion used in an ink jet printer.

  For example, as described in Patent Document 1, the lower electrode (lower electrode 60) is often formed as a series of large patterns as a common electrode of each piezoelectric element (TFP: Thin Film Piezo).

  On the other hand, in order to increase the nozzle density for the purpose of high-definition printing, it is necessary to narrow the cavity width. If the cavity width is narrowed, the restraining force increases effectively, so that the amount of displacement of the elastic plate (vibrating plate) decreases, and a desired amount of piezoelectric displacement cannot be obtained. As a result, the ink discharge amount decreases.

  For example, when the nozzle density of the cavity is doubled, that is, when the cavity width is halved, the thickness of the elastic plate positioned below the piezoelectric film is reduced to about 1/2 in order to obtain the same amount of piezoelectric displacement. 2 is required. In the case of an elastic plate, even if the film thickness is halved, it can function as an elastic plate, but the lower electrode located in the lower layer of the piezoelectric film has a function as a base for the piezoelectric film. Therefore, it cannot simply be thinned.

  That is, when the lower electrode is thin, the crystal orientation of the piezoelectric film (PZT) is lowered and the effective piezoelectric constant is lowered. As a result, the amount of displacement decreases after all.

  Therefore, a specific aspect of the present invention aims to provide a droplet discharge head that can improve the characteristics, and in particular, can improve the amount of displacement. It is another object of the present invention to provide a method for manufacturing a high-performance droplet discharge head.

  The droplet discharge head according to the present invention is partitioned by first and second piezoelectric elements arranged on the upper part of the vibration plate and arranged in the first direction, and at the lower part of the vibration plate by a partition, and the first and second First and second cavities arranged corresponding to the piezoelectric elements respectively, and the first and second piezoelectric elements are respectively formed of a lower electrode, a piezoelectric film and an upper electrode from the diaphragm side. The piezoelectric film is disposed at a substantially central portion in the first direction of the cavity, and the width of the piezoelectric film in the first direction is larger than the width of the cavity in the first direction. A first region which is small and has a cavity forming region on both sides of the piezoelectric film in the first direction and which does not serve as the piezoelectric film forming region; A conductive film common to the piezoelectric elements of the first, A first electrode portion disposed in the piezoelectric film forming region of the electric element; a second electrode portion disposed in the piezoelectric film forming region of the second piezoelectric element; and an opening portion disposed in the first region. And a bridge portion arranged alternately with the opening and connecting the first electrode portion and the second electrode portion.

  According to such a configuration, the lower electrode in the first region where the piezoelectric film forming region and the cavity forming region do not overlap by disposing the openings and the bridge portions alternately between the piezoelectric film forming regions. It becomes the structure from which was removed, and the amount of displacement can be improved. Moreover, since the lower electrode of each piezoelectric element part is connected by the bridge part, a common potential can be uniformly applied to each piezoelectric element. The openings may be thin film portions, and the thin film portions and thick film portions (bridge portions) may be alternately arranged.

  For example, the lower electrode further includes a connection portion that connects the bridge portions in a second direction intersecting the first direction between the cavity formation regions of the first and second piezoelectric elements. As described above, it is sufficient that at least the first region has an opening, and a connection portion may be provided between the cavity forming regions.

  For example, the piezoelectric film has a substantially rectangular shape having a long side in a second direction intersecting the first direction. In this way, the piezoelectric film may be substantially rectangular.

  Preferably, the lower electrode has a lattice pattern. Thus, the lower electrode may be a lattice pattern.

  For example, the lower electrode contains platinum (Pt) or iridium (Ir). As described above, even when an electrode material that is not easily deformed is used, the amount of displacement can be secured.

  The ink jet printer according to the present invention has the droplet discharge head as an ink discharge head. According to this configuration, it is possible to improve the characteristics of the ink jet printer.

  The method for manufacturing a droplet discharge head according to the present invention includes a step of forming a vibration plate on a substrate, a conductive film is formed on the vibration plate, and the conductive film is selectively removed. Forming a lower electrode having an opening, forming a piezoelectric film on a region excluding the opening, forming an upper electrode on the piezoelectric film, and forming a lower electrode on the diaphragm. By selectively removing the substrate, a cavity corresponding to the piezoelectric film is formed, the width in the first direction is larger than the width in the first direction of the piezoelectric film, and the cavity overlaps with the opening. And a step of performing.

  According to this manufacturing method, the lower electrode of the region (arm portion) where the piezoelectric film forming region and the cavity forming region do not overlap is removed between the piezoelectric film forming regions, and the displacement amount is large. A droplet discharge head can be manufactured. The opening may not be completely opened but may be a thin film portion.

  The method of manufacturing a droplet discharge head according to the present invention includes a step of forming a diaphragm on a substrate, a step of forming a conductive film on the diaphragm, and a piezoelectric film on the conductive film. Forming an upper electrode on the piezoelectric film; forming a lower electrode having an opening by selectively removing the conductive film on both sides of the piezoelectric film; A cavity corresponding to the piezoelectric film by selectively removing the substrate below the diaphragm, wherein a width in a first direction is larger than a width in the first direction of the piezoelectric film, and the opening Forming a cavity overlapping the portion.

  Also in this case, the lower electrode of the region (arm portion) where the piezoelectric film forming region and the cavity forming region do not overlap is removed between the piezoelectric film forming regions, and the droplet discharge with a large displacement amount is performed. A head can be manufactured. Thus, after forming the piezoelectric film, the opening of the lower electrode may be formed. The opening may not be completely opened but may be a thin film portion.

  For example, the piezoelectric film is crystal-grown using the lower electrode as a base film. According to this method, since the film thickness of the lower electrode is secured in the piezoelectric film forming region, the crystal orientation of the piezoelectric film can be improved and the piezoelectric constant can be improved.

  For example, the piezoelectric film has a substantially rectangular shape having a long side in a second direction intersecting the first direction. In this way, the piezoelectric film may be substantially rectangular.

  Preferably, the lower electrode has a lattice pattern. Thus, the lower electrode may be a lattice pattern.

  For example, the lower electrode contains platinum (Pt) or iridium (Ir). As described above, even when an electrode material that is not easily deformed is used, the amount of displacement can be secured.

  For example, the piezoelectric film is a PZT (lead zirconate titanate) film. Thus, a PZT film may be used.

  An ink jet printer manufacturing method according to the present invention includes the above-described droplet discharge head manufacturing method. According to this method, a high-performance inkjet printer can be manufactured.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same or related code | symbol is attached | subjected to what has the same function, and the repeated description is abbreviate | omitted.

(Droplet ejection head configuration)
FIG. 1 is a cross-sectional view of a main part and a plan view showing the configuration of a droplet discharge head according to the present embodiment. As shown in FIG. 1A, the droplet discharge head according to the present embodiment includes a piezoelectric element Pi disposed on the surface (first surface) of the diaphragm 13 and the back surface (second surface) of the diaphragm 13. ) And a cavity Ca that is partitioned by the partition wall (11) and disposed corresponding to the piezoelectric element Pi, and a nozzle plate 21 that closes the cavity Ca and has a nozzle hole 21a.

The diaphragm 13 is, for example, a laminated film of a silicon oxide (SiO ₂ ) film 13a and a zirconium oxide (ZrO ₂ ) film 13b.

  The piezoelectric element Pi has a laminated structure of a lower electrode 15, a piezoelectric film 17, and an upper electrode 19 from the diaphragm 13 side. The piezoelectric film 17 is disposed at a substantially central portion of the cavity Ca, and is formed on both sides thereof. There is a cavity forming area CA called an arm portion 20 where the piezoelectric film 17 is not formed. Specifically, the width (Wp1) of the piezoelectric film 17 is smaller than the width (Wc1) of the cavity Ca, and on both sides of the piezoelectric film, the arm portion 20 has a half width of “Wc1−Wp1” (for example, There is a region with a width of about 7 μm.

  The arm portion 20 is provided to increase the displacement amount of the diaphragm 13. The relationship between the width (Wp1) of the piezoelectric film 17 and the displacement amount is, for example, the relationship shown in FIG. 1D, and has a maximum value in the range of Wc1> Wp1.

  Here, in the droplet discharge head of the present embodiment, as shown in FIG. 1B, the arm 20 has a structure in which the lower electrode 15 is removed, and therefore, the broken line in FIG. As shown, the restraining force by the lower electrode 15 is relaxed, and the displacement amount of the diaphragm 13 can be increased.

  As shown in FIG. 1 (C), the lower electrode 15 is partially removed as an opening OA1 (FIG. 1 (B)), and in other parts, electrical conduction between the lower electrodes 15 is established. It extends as the bridge part BA to plan (FIG. 1 (A)).

  For example, as shown in FIG. 1C, the lower electrode 15 is formed in a lattice shape, and the openings OA1 and the bridges BA are alternately arranged, thereby ensuring both the displacement amount and the electrical continuity. Can be planned. For example, FIG. 1A corresponds to a cross section taken along a line AA in FIG. 1C, and FIG. 1B corresponds to a cross section taken along a line BB in FIG.

  In addition, since the amount of displacement can be increased, low-pressure driving is possible, and drive controllability can be improved. Furthermore, since the amount of displacement can be increased, it is possible to easily cope with miniaturization and high integration of the head.

  In FIG. 1A and the like, only one piezoelectric element Pi is shown. However, in a normal droplet discharge head, piezoelectric elements Pi are arranged in one or more rows, for example, 1 inch. Between 360 and 600 piezoelectric elements are arranged therebetween.

(Droplet ejection head manufacturing process)
2 to 8 are process cross-sectional views or plan views showing a method for manufacturing a droplet discharge head (liquid discharge head, ink jet head) according to the present embodiment. The manufacturing method of the droplet discharge head of the present embodiment will be described with reference to FIGS.

As shown in FIG. 2A, for example, a silicon substrate 11 having a plane orientation (110) is prepared as a first substrate (flow path forming substrate, processed substrate, sidewall material). Note that a material substrate other than silicon may be used as the first substrate. Next, as shown in FIGS. 2B and 2C, silicon oxide (vibration film, elastic plate, elastic film, actuator plate) 13 is formed on the surface (first surface) of the silicon substrate 11 as silicon oxide ( A laminated film of SiO ₂ ) film 13a and zirconium oxide (ZrO ₂ ) film 13b is formed. For example, the surface of the silicon substrate 11 is thermally oxidized to form a silicon oxide film 13a having a thickness of about 1000 nm (FIG. 2B). Next, for example, a zirconium film is deposited on the silicon oxide film 13a by a sputtering method, and the zirconium film is thermally oxidized to form a zirconium oxide film 13b having a thickness of about 500 nm (FIG. 2C). In addition, you may comprise the diaphragm 13 using another insulating film. Further, the diaphragm 13 may be constituted by a single insulating film (for example, SiO ₂ ).

The diaphragm 13 is subjected to the displacement of the piezoelectric film 17 so that the diaphragm itself bends and changes the volume of the cavity Ca. In addition to the function as a diaphragm, the zirconium oxide film 13b plays a role of preventing diffusion of lead (Pb) atoms generated when the piezoelectric film (PZT film) 17 is fired. When Pb atoms diffuse, a PbO layer is formed at the SiO ₂ layer interface, and this PbO layer reduces the adhesion and causes peeling.

  Next, as shown in FIG. 3A, a laminated film of, for example, an iridium (Ir) film and platinum (Pt) is formed on the diaphragm 13 as the lower electrode 15. For example, after depositing an Ir film with a thickness of about 10 nm by a sputtering method, a Pt film is deposited with a thickness of about 150 nm by a sputtering method. Next, as shown in FIGS. 3B and 3C, the laminated film is patterned into a lattice shape having an opening OA1. That is, a photoresist film is formed on the laminated film, and a lattice-like photoresist film is formed by exposure and development (photolithography). Next, the lower electrode 15 is formed by etching the laminated film using the photoresist film as a mask. Next, the remaining photoresist film is removed. A series of steps from formation to removal of the photoresist film is called patterning.

  Here, the shape (pattern) of the lower electrode 15 will be described with reference to FIGS. 3 and 4. As shown in FIG. 3C, the outer periphery of the lower electrode 15 is substantially rectangular and has a plurality of openings OA1 therein. The openings OA1 are substantially rectangular and are arranged in an array with a predetermined interval. Between the openings OA1 arranged in the x direction, a bridge (connection area) BA is formed. When the width in the x direction of the bridge portion BA is a and the width in the x direction of the opening OA1 is b, for example, a is about 20 μm and b is about 100 μm.

  In other words, the shape of the lower electrode 15 is a lattice shape. A portion (wiring) extending in the x direction intersects with a portion (wiring) extending in the y direction. The width of the portion extending in the y direction is a. In FIG. 4, PA is a piezoelectric film forming region, and is a region where a piezoelectric film 17 described later is formed. Further, CA is a cavity forming region, and is a region where a cavity Ca described later is formed. The width of the portion extending in the x direction is the width (Wp1) of the piezoelectric film forming region PA.

As shown in FIG. 4A, the piezoelectric film forming area PA and the cavity forming area CA have a substantially rectangular shape having long sides in the x direction, and the piezoelectric body forming area PA is in the y direction of the cavity forming area CA. It is arrange | positioned in the approximate center part. That is, there are areas where no piezoelectric film exists on both sides of the cavity forming area CA in the y direction. Therefore, in patterning the lower electrode 15,
In the cavity forming area CA on both sides in the y direction of the piezoelectric body forming area PA, in other words, in the cavity forming area CA that is not the piezoelectric body forming area PA (arm portion 20, hatched portion in FIG. 4B), The openings OA1 and the bridges BA are alternately arranged.

  Thereby, as described above, the arm portion 20 is released from the restraining force of the lower electrode 15 and is easily displaced (see FIG. 1B). In particular, Pt and Ir, which are materials of the lower electrode 17 of the present embodiment, are not easily deformed (Young's modulus is 200 to 300 GPa), but with the above configuration, the amount of displacement can be ensured even when such materials are used.

  On the other hand, since each piezoelectric element Pi (electrode part, segment) is connected by a bridge part BA, it is possible to achieve electrical conduction between the lower electrode parts, and to each piezoelectric element Pi uniformly at once. Can be applied. In addition, the formation area is increased by the bridge portion BA, and the resistance of the electrode can be reduced.

Next, as shown in FIG. 5A, as the piezoelectric film 17, for example, a PZT (lead zirconate titanate, Pb (Zr _1-x Ti _x ) O ₃ ) film is formed on the lower electrode 15. The PZT film is formed by, for example, a so-called sol-gel method in which a metal organometallic compound solution constituting the film is applied onto the lower electrode 15 and then dried and fired. The baking temperature is set to about 700 ° C., for example, and a PZT film having a film thickness of about 1.0 μm is formed at a composition ratio of Zr and Ti of about 50% (x = 0.5). This PZT film has a monoclinic structure preferentially oriented to (100), and has an engineered domain arrangement in which the polarization direction is inclined by a certain angle with respect to the direction perpendicular to the plane of the film. The lattice constant of the PZT film is approximately 4.05 mm, and specifically, c1 <a1 where c1 is the direction perpendicular to the plane and a1 is the in-plane direction. Thus, in the present embodiment, since the displacement can be improved by the opening OA1 of the lower electrode 15, the film thickness of the lower electrode 15 in the piezoelectric film forming region PA (for example, a film thickness of 120 nm or more). Can be secured. Therefore, the piezoelectric characteristics can be improved by maintaining and improving the crystal orientation of the PZT film.

  Next, as shown in FIG. 5B, for example, an Ir film is formed on the piezoelectric film 17 as the upper electrode 19. The Ir film is deposited to a thickness of about 200 nm by sputtering. Next, the piezoelectric film 17 and the upper electrode 19 are patterned into a desired shape, for example, a plurality of substantially rectangular shapes arranged in the y direction (for example, a rectangle of 40 μm × 600 μm, see FIG. 6C). The pattern corresponds to the piezoelectric film forming area PA, and a cavity Ca is formed below each pattern. 6C is a plan view, FIG. 6A corresponds to the AA cross section of FIG. 6C, and FIG. 6B corresponds to the BB cross section of FIG. 6C. To do.

  Through the above steps, the piezoelectric element Pi composed of the lower electrode 15, the piezoelectric film 17 and the upper electrode 19 is formed on the vibration plate 13.

  Next, as shown in FIG. 7, by selectively removing the silicon substrate 11, a cavity (pressure chamber, space) Ca and a reservoir (flow path) R are formed below the piezoelectric film 17.

  That is, a photoresist film is formed on the back surface (second surface) of the silicon substrate 11 and exposed and developed to form a photoresist film having openings at positions corresponding to the cavities Ca and the reservoirs R. Next, the silicon substrate 11 is etched using the film as a mask until the vibration plate (silicon oxide film 13a) 13 is exposed. As the etchant, for example, a potassium hydroxide (KOH) solution is used. At this time, the silicon oxide film 13a constituting the vibration plate 13 serves as an etching stopper. The hatched portion in FIG. 7C is the remaining portion of the silicon substrate 11. FIG. 7C is a plan view seen from the back side of the silicon substrate 11. 7A corresponds to the CC cross section of FIG. 7C, and FIG. 7B corresponds to the BB cross section of FIG. 7C (the same applies to FIG. 8).

  The remaining silicon substrate 11 serves as a partition partitioning the cavity Ca. For example, the width of the reservoir R is about 200 μm, the width of the cavity Ca is 55 μm, the length is 800 μm, and the height is about 60 μm. In addition, between the cavity Ca and the reservoir | reserver R, the connection flow path (squeezing) Cb whose width | variety is narrower than the width | variety (Wc1) of the y direction of cavity Ca part is formed.

  Next, as shown in FIG. 8, a nozzle plate (second substrate, bonding substrate, support substrate, flat plate member) 21 having a nozzle hole 21a is bonded to the lower side of the cavity Ca. The nozzle plate 21 is made of, for example, a silicon substrate and has a thickness of, for example, about 60 μm. FIG. 8C is a plan view seen from the back side of the nozzle plate 21.

  The nozzle hole 21a of the nozzle plate 21 is formed by etching the nozzle plate 21 and has a diameter of, for example, about 20 μm. For example, a KOH solution is used as an etchant, and a silicon oxide film is used as an etching mask, for example.

  The nozzle holes 21a are aligned so as to correspond to the cavities Ca, and, for example, the silicon substrate 11 and the nozzle plate 21 are joined by thermocompression bonding.

  Next, a supply hole for supplying ink (solution) to the reservoir R is processed as necessary.

  Through the above steps, the droplet discharge head according to the present embodiment is substantially completed. The applied voltage to the piezoelectric element Pi is, for example, about 20 V, and the displacement amount of the diaphragm 13 is, for example, about 400 nm. Further, the discharge amount of droplets (ink) is, for example, about 4 picoliters, and the discharge speed is about 8 m / sec.

  FIG. 9 is an exploded perspective view of the droplet discharge head according to the present embodiment. As shown in the drawing, a compliance substrate 41 may be disposed on the diaphragm 13 as necessary. The compliance substrate 41 is provided with, for example, a piezoelectric element holding portion 41a and opening areas 41b and 41c. A lead electrode E is exposed from the opening region 41b, and the lead electrode E is connected to a drive IC (not shown). In FIG. 7 and the like, the lead electrode E is omitted.

  Hereinafter, application examples of the above embodiment will be described. 10 to 12 are cross-sectional views or plan views showing other configurations and the like of the droplet discharge head according to the present embodiment. In addition, in the following application examples 1-3, since it is the same as that of said case except the shape and formation process of the lower electrode 15 differing, the description of the detailed structure and manufacturing process is abbreviate | omitted.

(Application 1)
In the above embodiment, the opening OA1 is provided in the lower electrode 15, but the portion may be the thin film portion TA.

  That is, in the patterning of the lower electrode 15 described with reference to FIG. 3, the etching is not completed until the lower diaphragm 13 is exposed, and the process is terminated halfway. As shown in FIG. The thin film portions TA and the bridge portions BA may be alternately arranged on the arm portion 20. According to such a configuration, as shown in FIG. 10C, the restraining force of the lower electrode 15 in the arm portion 20 can be reduced, and the amount of displacement can be improved. 10B corresponds to the AA cross section of FIG. 10A, and FIG. 10C corresponds to the BB cross section of FIG. 10A.

(Application example 2)
In the above embodiment, the opening OA1 of the lower electrode 15 is patterned, and then the piezoelectric film 17 and the like are patterned. However, as shown in FIG. After the patterning, the piezoelectric film 17 and the like are patterned (FIG. 11B), and the lower electrode 15 is exposed between the piezoelectric films 17, and then the opening OA1 may be formed (FIG. 11C). ). The plan view in this case is the same as FIG.

  At this time, the thin film portion TA may be used instead of the opening OA1. A sectional view and a plan view in this case are the same as those in FIG. Thus, when the opening OA1 and the thin film portion TA are formed after crystal growth of the piezoelectric film 17, the number of steps increases, but the crystallinity is improved.

(Application 3)
In the above embodiment, the side extending in the y direction of the opening OA1 is made equal to the distance between the piezoelectric films 17, but as shown in FIG. 12, the lower electrode is formed on the partition between the cavities Ca. 15 may be left. That is, it is good also as the shape which connected between the bridge parts BA by the connection part 30 in the x direction. Also in this case, as shown in FIG. 12A, the outer periphery of the lower electrode 15 is substantially rectangular and has a plurality of openings OA2. The openings OA2 are substantially rectangular and are arranged in an array at a predetermined interval.

  In other words, the shape of the lower electrode 15 is a lattice shape. That is, a portion (wiring) extending in the x direction intersects with a portion (wiring) extending in the y direction. The width of the portion extending in the y direction is a. In the portion extending in the x direction, the portion having the width (Wp1) of the piezoelectric film forming region PA and the portion having the width corresponding to the distance D between the cavities Ca are alternately arranged.

  The shape of the lower electrode 15 is larger than the shape shown in FIG. 3C, has a smaller resistance, and can apply a more uniform potential.

  Also in the droplet discharge head shown in FIG. 12, the opening OA2 portion of the lower electrode 15 may be the thin film portion TA. Also in the droplet discharge head shown in FIG. 12, the lower electrode 15 is once patterned into a substantially rectangular shape, and then the piezoelectric film 17 and the like are patterned (FIG. 12B). After exposing between the openings 17, the opening OA2 may be formed (FIG. 12C). At this time, the thin film portion TA may be used instead of the opening OA2.

(Example)
FIG. 13 is a table showing characteristics (voltage displacement amount) of the droplet discharge head of the above embodiment.

  As shown in FIG. In the case of 1, the head of the lower electrode configuration shown in FIG. 3C, that is, the arm portion 20 has an opening, and there is also an opening between the cavities (that is, there is no connection portion 30). The displacement amount was 410 nm, and the displacement amount increased from the comparative example (displacement amount: 370 nm) in which no opening was provided in the arm portion 20. No. 2 (the head having the lower electrode configuration shown in FIG. 12A), when the arm portion 20 has an opening and there is no opening between the cavities (that is, the connection portion 30 is present), the displacement amount is 405 nm. Also in this case, the amount of displacement increased compared to the comparative example.

  The bridge width a was 50 μm, the applied voltage was 0 to 35 V, and the displacement was measured using a laser Doppler meter.

  Next, as shown in FIG. 1 (lower electrode configuration shown in FIG. 3C), the ratio (a / b) is changed when the width in the x direction of the bridge portion BA is a and the width in the x direction of the opening OA1 is b. The amount of displacement was measured. Here, it is shown as a ratio when the displacement amount of the comparative example is 1. The displacement increases as a / b decreases from 0.5 to 0.2.

  Thus, by providing an opening part, it has confirmed that a displacement amount became large, and also the displacement amount increased as the width | variety (a) of a bridge part became small. In addition, about a / b, it is thought that 0.3 or less is especially preferable.

(Inkjet printer)
FIG. 14 is a perspective view showing an example of an ink jet printer to which the droplet discharge head of the present embodiment is applied.

  For example, the ink jet printer 600 includes an apparatus main body 620, has a tray 621 for installing the recording paper P in the upper rear, has a discharge port 622 for discharging the recording paper P in the lower front, and operates on the upper surface. A panel 670 is provided.

  Inside the apparatus main body 620, there are mainly a printing apparatus 640 provided with a reciprocating head unit 630, a paper feeding apparatus 650 for feeding the recording paper P one by one to the printing apparatus 640, the printing apparatus 640 and the paper feeding apparatus. A control unit 660 for controlling the 650 is provided.

  Under the control of the control unit 660, the paper feeding device 650 intermittently feeds the recording paper P one by one. The recording paper P that is intermittently fed passes near the lower portion of the head unit 630. At this time, the head unit 630 reciprocates in a direction substantially perpendicular to the feeding direction of the recording paper P, and printing on the recording paper P is performed. That is, the reciprocating motion of the head unit 630 and the intermittent feeding of the recording paper P are the main scanning and sub-scanning in printing, and ink jet printing is performed.

  The printing apparatus 640 includes a head unit 630, a carriage motor 641 serving as a drive source for the head unit 630, and a reciprocating mechanism 642 that reciprocates the head unit 630 in response to the rotation of the carriage motor 641.

  The head unit 630 has an ink jet recording head 50 provided with the above-described many ejection holes (nozzle holes) 21a in the lower portion thereof, an ink cartridge 631 for supplying ink to the ink jet recording head 50, and the ink jet recording head 50. And a carriage 632 on which the ink cartridge 631 is mounted.

  By using an ink cartridge 631 filled with, for example, four colors of yellow, cyan, magenta, and black (black), full-color printing can be performed. In this case, the head unit 630 is provided with the ink jet recording head 50 corresponding to each color.

  The reciprocating mechanism 642 includes a carriage guide shaft 643 whose both ends are supported by a frame (not shown), and a timing belt 644 extending in parallel with the carriage guide shaft 643. The carriage 632 is supported by the carriage guide shaft 643 so as to reciprocate and is fixed to a part of the timing belt 644. When the timing belt 644 travels forward and backward through a pulley by the operation of the carriage motor 641, the head unit 630 reciprocates while being guided by the carriage guide shaft 643. During this reciprocation, ink is appropriately discharged from the ink jet recording head 50 and printing on the recording paper P is performed.

  The sheet feeding device 650 includes a sheet feeding motor 651 serving as a driving source thereof, and a sheet feeding roller 652 that is rotated by the operation of the sheet feeding motor 651. The paper feed roller 652 is composed of a driven roller 652 a and a drive roller 652 b that are opposed to each other across the feeding path (recording paper P) of the recording paper P, and the driving roller 652 b is connected to the paper feeding motor 651. Has been. With such a configuration, the paper feed roller 652 can feed a large number of recording sheets P installed on the tray 621 one by one toward the printing apparatus 640. Note that, instead of the tray 621, a configuration in which a paper feed cassette that stores the recording paper P can be detachably mounted can be employed.

  The control unit 660 performs printing by controlling the printing device 640, the paper feeding device 650, and the like based on print data input from a host computer such as a personal computer or a digital camera.

  Although not shown in the figure, the control unit 660 mainly includes a memory that stores a control program for controlling each unit, a piezoelectric element drive circuit that drives a piezoelectric element (vibration source) to control ink ejection timing, and a printing apparatus. A drive circuit for driving 640 (carriage motor 641), a drive circuit for driving paper feed device 650 (paper feed motor 651), and a communication circuit for obtaining print data from the host computer, and electrically connected thereto, CPU which performs various control in each part is provided.

  For example, various sensors capable of detecting a printing environment such as the remaining amount of ink in the ink cartridge 631, the position of the head unit 630, temperature, and humidity are electrically connected to the CPU. The control unit 660 obtains print data via the communication circuit and stores it in the memory. The CPU processes the print data and outputs a drive signal to each drive circuit based on the process data and input data from various sensors. The piezoelectric element, the printing device 640, and the paper feeding device 650 are operated by this drive signal. Thus, desired printing is performed on the recording paper P.

  According to the ink jet printer 600 according to the present embodiment, as described above, since the head having good droplet discharge characteristics is provided, high-density printing and high-speed printing are possible. Further, by incorporating the above-described head into the ink jet printer 600, the productivity can be improved.

  The ink jet printer 600 of the present invention can also be used as a droplet discharge device used industrially. In that case, as the ink to be ejected (liquid material), various functional materials can be used by adjusting them to an appropriate viscosity with a solvent or a dispersion medium.

  It should be noted that the examples and application examples described through the above embodiment can be used in appropriate combination according to the application, or can be used with modifications or improvements, and the present invention is limited to the description of the above embodiment. Is not to be done.

FIG. 2 is a cross-sectional view and a plan view of main parts showing a configuration of a droplet discharge head according to the present embodiment. It is process sectional drawing which shows the manufacturing method of the droplet discharge head of this Embodiment. It is process sectional drawing and a top view which show the manufacturing method of the droplet discharge head of this Embodiment. It is a top view which shows the manufacturing method of the droplet discharge head of this Embodiment. It is process sectional drawing which shows the manufacturing method of the droplet discharge head of this Embodiment. It is process sectional drawing and a top view which show the manufacturing method of the droplet discharge head of this Embodiment. It is process sectional drawing and a top view which show the manufacturing method of the droplet discharge head of this Embodiment. It is process sectional drawing and a top view which show the manufacturing method of the droplet discharge head of this Embodiment. It is a disassembled perspective view of the droplet discharge head of this Embodiment. It is sectional drawing and a top view which show the other structure of the droplet discharge head of this Embodiment. It is process sectional drawing and a top view which show the other manufacturing method of the droplet discharge head of this Embodiment. It is sectional drawing and a top view which show the other structure of the droplet discharge head of this Embodiment. It is a table | surface which shows the characteristic (voltage displacement amount) of the droplet discharge head of this Embodiment. 1 is a perspective view illustrating an example of an inkjet printer to which a droplet discharge head according to an embodiment is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Silicon substrate, 13 ... Diaphragm, 13a ... Silicon oxide film, 13b ... Zirconium oxide film, 15 ... Lower electrode, 17 ... Piezoelectric film, 19 ... Upper electrode, 20 ... Arm part, 21 ... Nozzle plate, 21a ... Nozzle hole, 30 ... connection part, 41 ... compliance substrate, 41a ... piezoelectric element holding part, 41b, 41c ... opening area, 600 ... inkjet printer, 620 ... main body, 621 ... tray, 622 ... discharge port, 630 ... head unit , 631 ... Ink cartridge, 632 ... Carriage, 640 ... Printing device, 641 ... Carriage motor, 642 ... Reciprocating mechanism, 643 ... Carriage guide shaft, 644 ... Timing belt, 650 ... Paper feed device, 651 ... Paper feed motor, 652 ... feed roller, 660 ... control unit, 670 ... operation panel, a ... width of bridge, b ... opening , BA ... bridge, CA ... cavity formation region, Ca ... cavity, Cb ... connection flow path, E ... lead electrode, OA1, OA2 ... opening, Pi ... piezoelectric element, PA ... piezoelectric film formation region, R ... reservoir, TA ... thin film portion, Wp1 ... width of piezoelectric film (formation region), Wc1 ... width of cavity (formation region)

Claims (14)

First and second piezoelectric elements arranged on the top of the diaphragm and arranged in the first direction;
A first cavity and a second cavity that are partitioned by a partition wall and are respectively disposed corresponding to the first and second piezoelectric elements;
The first and second piezoelectric elements each have a laminated structure of a lower electrode, a piezoelectric film and an upper electrode from the diaphragm side,
The piezoelectric film is disposed at a substantially central portion of the cavity in the first direction, and the width of the piezoelectric film in the first direction is smaller than the width of the cavity in the first direction. A first region that is a region where the cavity is formed on both sides of the first direction and which does not become a region where the piezoelectric film is formed;
The lower electrode is a conductive film common to the first and second piezoelectric elements;
A first electrode portion disposed in a piezoelectric film forming region of the first piezoelectric element;
A second electrode portion disposed in a piezoelectric film forming region of the second piezoelectric element;
A droplet discharge head comprising: an opening portion disposed in the first region; and a bridge portion that is alternately disposed with the opening portion and connects the first electrode portion and the second electrode portion. . The lower electrode further includes:
2. The liquid according to claim 1, further comprising a connection portion that connects the bridge portions in a second direction intersecting the first direction between the cavity formation regions of the first and second piezoelectric elements. Drop ejection head.   The droplet discharge head according to claim 1, wherein the piezoelectric film has a substantially rectangular shape having a long side in a second direction intersecting the first direction.   The liquid droplet ejection head according to claim 1, wherein the lower electrode has a lattice pattern.   5. The liquid droplet ejection head according to claim 1, wherein the lower electrode contains platinum (Pt) or iridium (Ir).   An ink jet printer comprising the droplet discharge head according to any one of claims 1 to 5 as an ink discharge head. Forming a diaphragm on the substrate;
Forming a conductive film on the vibration plate and selectively removing the conductive film to form a lower electrode having an opening; and
Forming a piezoelectric film on a region excluding the opening;
Forming an upper electrode on the piezoelectric film;
A cavity corresponding to the piezoelectric film by selectively removing the substrate below the diaphragm, wherein a width in a first direction is larger than a width in the first direction of the piezoelectric film, and the opening Forming a cavity that overlaps with the part;
A method of manufacturing a droplet discharge head, comprising: Forming a diaphragm on the substrate;
Forming a conductive film on the diaphragm;
Forming a piezoelectric film on the conductive film;
Forming an upper electrode on the piezoelectric film;
Forming a lower electrode having an opening by selectively removing the conductive film on both sides of the piezoelectric film;
A cavity corresponding to the piezoelectric film by selectively removing the substrate below the diaphragm, wherein a width in a first direction is larger than a width in the first direction of the piezoelectric film, and the opening Forming a cavity that overlaps with the part;
A method of manufacturing a droplet discharge head, comprising:   9. The method of manufacturing a droplet discharge head according to claim 7, wherein the piezoelectric film is crystal-grown using a lower electrode as a base film.   10. The method of manufacturing a droplet discharge head according to claim 7, wherein the piezoelectric film has a substantially rectangular shape having a long side in a second direction intersecting the first direction. .   The method of manufacturing a droplet discharge head according to claim 7, wherein the lower electrode has a lattice pattern.   The method of manufacturing a droplet discharge head according to claim 7, wherein the lower electrode contains platinum (Pt) or iridium (Ir).   13. The method of manufacturing a droplet discharge head according to claim 7, wherein the piezoelectric film is a PZT (lead zirconate titanate) film.   14. A method for manufacturing an ink jet printer, comprising the method for manufacturing a droplet discharge head according to claim 7 as a method for manufacturing an ink discharge head.

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