JP2010105184A - Droplet delivery device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a droplet delivery device capable of satisfactorily separating a delivered liquid-like object. <P>SOLUTION: This droplet delivery device includes a nozzle plate 121 with an opened nozzle 125, a flow channel forming substrate 127 provided on the nozzle plate 121, and having a storage chamber 122, a reservoir 124 and a supply passage 123, a vibration plate 128 provided on the flow channel forming substrate 127, and having a needle 126 with the center consistent with that of the nozzle 125, and a piezoelectric driving element 129 provided on the vibration plate 128 and in an upper part of the storage chamber 122, and comprising a lower electrode 129a, a piezoelectric element 129b and an upper electrode 129c. A tip of the needle 126 has an insertion-through part inserted through into the nozzle 125 under the condition where the needle 126 comes down, with vertical vibration by the piezoelectric driving element 129. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a droplet discharge device.

  Conventionally, a droplet discharge apparatus has been used in a wide range of fields as a printer for forming an image and a film forming apparatus for manufacturing a device. In general, the droplet discharge device includes a large number of discharge units. The discharge unit includes a liquid storage unit, a nozzle communicating with the storage unit, a piezoelectric element that pressurizes the liquid and pushes liquid droplets out of the nozzle.

  In recent years, a film forming technique using a droplet discharge method has attracted attention. According to the droplet discharge method, it is possible to place minute droplets containing a film forming material at a desired position. Thereby, a fine film pattern can be formed, and patterning becomes easier than in the case of using a photolithography method. In addition, since the waste of the film forming material can be reduced, the manufacturing cost can be reduced.

  In such industrial use, a highly viscous liquid material such as a polymer ink may be ejected as a film forming material. Further, even in image printing applications, a highly viscous liquid material such as UV ink may be ejected. In order to dispose a high-viscosity liquid material at a high-precision position in a high-definition pattern, it is extremely important to separate the liquid material as fine droplets from a meniscus (liquid surface) in the nozzle.

As a technique for separating droplets, a technique disclosed in Patent Document 1 can be cited. The droplet discharge device of Patent Document 1 includes a pin-shaped ink guide that is inserted into a nozzle. The ink guide gives a stimulus such as vibration to the ink (liquid material) to divide the kite string.
JP 2005-178325 A

  If the technique of Patent Document 1 is used, the kite string can be divided and the liquid material can be separated as fine droplets. However, when the ink guide is vibrated, the ejected liquid material vibrates and causes flight bending, which may reduce the landing accuracy. Further, when thermal stimulation is given by the ink guide, drying of the liquid material is promoted in the vicinity of the nozzle, which may cause nozzle clogging.

  Further, when the ink guide penetrates the meniscus and the meniscus changes with the ejection operation, the liquid material adheres to the ink guide in the portion exposed to the gas phase. When the attached liquid material is dried and detached, there is a possibility that it adheres as a foreign matter to the substrate to be processed. Further, since the ink guide is inserted through the nozzle and the ink flow path in the nozzle is narrow, there is a possibility that nozzle clogging is likely to occur.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a droplet discharge device that can satisfactorily separate a discharged liquid material.

  The droplet discharge device of the present invention includes a nozzle plate having a nozzle opening, a flow path forming substrate provided on the nozzle plate and having a storage chamber, a reservoir, and a supply path, and the flow path forming substrate. A diaphragm having a needle whose center coincides with the nozzle, and a piezoelectric driving element provided on the diaphragm and above the storage chamber, and comprising a lower electrode, a piezoelectric element, and an upper electrode. And the tip of the needle has an insertion portion that is inserted into the nozzle in a state where the needle comes down due to vertical vibration by the piezoelectric driving element.

  When the volume of the storage chamber is reduced by the vertical vibration by the piezoelectric driving element in a state where the liquid material is stored in the storage chamber, the liquid material is discharged from the nozzle by the amount of the decrease in the volume. According to the above configuration, the needle insertion portion is inserted into the nozzle in conjunction with the discharge of the liquid material from the nozzle. Accordingly, in a continuous portion where the discharged liquid material and the liquid material in the storage chamber are continuous in the nozzle, the cross-sectional area perpendicular to the axial direction of the nozzle is reduced by the insertion of the insertion portion. Therefore, the continuous portion is easily cut and the discharged liquid material is easily separated as droplets.

  As described above, according to the present invention, the tip portion can be separated without changing the physical properties of the liquid by heat, so that nozzle clogging due to drying of the liquid or deterioration of the liquid does not occur. , It is possible to perform a stable discharge operation. Therefore, a liquid ejecting apparatus capable of arranging a minute volume of liquid material at a highly accurate position and capable of forming a high-definition film pattern or image.

Moreover, it is preferable that the said insertion part becomes small as the outer dimension of the cross section orthogonal to the axial direction of the said nozzle goes to the opening on the opposite side to the said storage chamber in the said nozzle.
If it does in this way, the edge part by the side of the nozzle of an insertion part can be made to insert in a nozzle favorably by using as a guide.

  The insertion portion may be inserted through the nozzle until a part of the side surface of the insertion portion around the axial direction comes into contact with the inner wall of the nozzle. In this case, it is preferable that the side surface of the insertion portion is subjected to wear resistance treatment.

  When the insertion part is inserted into the nozzle until a part of the side surface around the axial direction of the insertion part comes into contact with the inner wall of the nozzle, the liquid material in the storage chamber and the discharged liquid material are surely inserted by the contact part. Divided. Therefore, the discharged liquid material becomes a good droplet, and the amount of the droplet is accurately defined, and the droplet can be discharged with a highly accurate discharge amount.

  In addition, if the side surface of the insertion portion is subjected to wear resistance, wear of the insertion portion due to contact between the side surface of the insertion portion and the inner wall of the nozzle can be reduced, and durability of the droplet discharge device can be improved. Can do.

In addition, the insertion portion has an end surface facing an opening of the nozzle opposite to the storage chamber, and a side surface around the axial direction of the insertion portion is lyophilic with respect to the liquid material. The end face is preferably liquid repellent with respect to the liquid.
In this way, the contact portion with the end face in the discharged liquid body is repelled because the end face is lyophobic, and the side surface is lyophilic, so the peripheral side of the end face Pulled on. Further, since the discharged liquid material moves in a direction away from the end face, the contact portion is also pulled in a direction away from the end face. Since the contact portion is pulled in two directions as described above, it is easily cut off, so that the discharged liquid material is reliably separated.

  Hereinafter, although one embodiment of the present invention is described, the technical scope of the present invention is not limited to the following embodiment. In the following description, various structures are illustrated using the drawings. However, in order to make the characteristic portions of the structure easy to see, the dimensions and scale of the structure are illustrated as appropriately different from the actual structure.

  FIG. 1 is a schematic perspective view showing a configuration of a film forming apparatus provided with a droplet discharge head (droplet discharge device) of the present embodiment. This film forming apparatus arranges a liquid material on a substrate to be processed by a droplet discharge method. The liquid body to be disposed contains a solid content such as a film material, and the solid content remains when dried. That is, the liquid material here is a dispersion (solution) in which a solid content is dispersed (dissolved) in a dispersion medium (solvent). Specific examples of the liquid include color filter materials containing pigments and dyes, colloidal solutions containing metal particles that are conductive film pattern forming materials such as UV ink and metal wiring.

  Such a liquid has a high viscosity, for example, having a viscosity of about 10 to 30 cP at room temperature. In addition, there is a liquid that has a viscosity exceeding 30 cP at normal temperature and is used by reducing the viscosity by heating at the time of discharge. Since the highly viscous liquid material has a thread-like tail between the meniscus after being discharged, it is difficult to separate from the meniscus. In the present embodiment, a film forming apparatus 1 for producing a color filter will be described as a film forming apparatus that uses a liquid material having a high viscosity as described above as a film material.

  As shown in FIG. 1, the film forming apparatus 1 includes a work stage 11 provided on a support base 10 and a droplet discharge head 12 provided at a position higher than the work stage 11. A substrate to be processed W can be placed on the upper surface of the work stage 11. The position of the work stage 11 and the droplet discharge head 12 is controlled by a control device (not shown). The control device controls the discharge operation of the droplet discharge head 12. With the configuration as described above, the liquid material can be disposed in a predetermined region of the substrate W to be processed from the droplet discharge head 12 while scanning the substrate W to be processed.

  Hereinafter, description will be made based on the XYZ orthogonal coordinate system shown in FIG. In this XYZ orthogonal coordinate system, the X axis and the Y axis are parallel to the surface direction of the work stage 11, and the Z axis is orthogonal to the surface direction of the work stage 11. Actually, the XY plane is set as a plane parallel to the horizontal plane, and the Z axis is set in the vertical upward direction. At the time of film formation, for example, after the liquid material is arranged along the main scanning direction, the position in the sub-scanning direction is adjusted, and the liquid material is arranged again along the main scanning direction. Here, the X-axis direction that is the moving direction of the work stage 11 is set as the main scanning direction, and the Y-axis direction that is the moving direction of the droplet discharge head 12 is set as the sub-scanning direction.

  The work stage 11 includes a vacuum suction device (not shown) and the like, and can detachably fix the placed substrate W to be processed. The work stage 11 is provided with a stage moving device 111. The stage moving device 111 includes a bearing mechanism such as a ball screw or a linear guide, and moves the work stage 11 in the X-axis direction based on a control signal input from the control device. Thereby, the substrate W to be processed can be moved to a predetermined position in the X direction.

  The film forming apparatus 1 includes three droplet discharge heads 12 corresponding to each of three types of color filter materials (red, green, and blue). All of the three liquid droplet ejection heads 12 are attached to the carriage 13, and the carriage 13 is provided with a carriage moving device 131. The carriage moving device 131 moves the carriage 13 in the X direction and the Y direction based on the control signal input from the control device. Thereby, the droplet discharge head 12 can be moved to a predetermined position in the X direction or the Y direction.

  Each of the three droplet discharge heads 12 includes a plurality of discharge units (described later). Each of the discharge units discharges the liquid material based on drawing data and control signals from the control device. Three types of liquid materials that are three types of color filter materials are stored in tanks 14A, 14B, and 14C, respectively. The stored liquid material is supplied to the corresponding droplet discharge head 12 through the tube group 141 for each type.

  2A to 2C are diagrams showing a schematic configuration of the droplet discharge head 12. 2A is a plan view showing a surface of the droplet discharge head 12 facing the substrate W, FIG. 2B is a cross-sectional view taken along the line AA ′ in FIG. 2A, and FIG. c) is an enlarged cross-sectional view of a needle and a nozzle.

  As shown in FIG. 2A, the droplet discharge head 12 includes a plurality of discharge units U arranged substantially orthogonal to the main scanning direction (X-axis direction). A common nozzle plate 121 is provided for the plurality of discharge units U. The nozzle plate 121 is provided with a nozzle 125 for each discharge unit U. The nozzles 125 are arranged along the arrangement direction (Y direction) of the discharge units U.

  The nozzle 125 communicates with the liquid storage chamber 122. The storage chamber 122 communicates with a common reservoir 124 in a plurality of discharge units U via a liquid supply path 123. Although the detailed shape of the supply path 123 is not illustrated, the liquid material does not flow backward from the storage chamber 122 to the reservoir 124. The reservoir 124 is connected to one of the tube groups 141 shown in FIG. The liquid material discharged from the discharge unit U is filled into the storage chamber 122 from the tanks 14A, 14B, and 14C through the tube group 141, the reservoir 124, and the supply path 123.

  As illustrated in FIG. 2B, the discharge unit U includes a nozzle plate 121, a vibration plate 128, and a flow path forming substrate 127 that is sandwiched between the nozzle plate 121 and the vibration plate 128. The flow path forming substrate 127 is provided with a through hole and a recess. The through holes and the recesses are sandwiched between the nozzle plate 121 and the vibration plate 128, thereby forming a liquid storage chamber 122 and a supply path 123. That is, a part of the diaphragm 128 is a wall surface of the storage chamber 122.

  A needle (insertion portion) 126 is provided on the diaphragm 128 on the side facing the nozzle plate 121 at a position overlapping the nozzle 125 in a plan view. The needle 126 of the present embodiment extends substantially perpendicular to the surface direction of the diaphragm 128. In the needle 126, a portion (hereinafter referred to as a main portion) connected to the diaphragm 128 is a substantially cylindrical shape, and an end portion (hereinafter referred to as a tip portion) on the nozzle 125 side is substantially smaller in diameter than the main portion. It is a cylinder. The intermediate part between the main part and the tip part has a truncated cone shape whose diameter is reduced toward the tip part. The needle 126 is preferably made of ceramics or tungsten carbon from the viewpoint of ensuring wear resistance.

  On the opposite side of the diaphragm 128 from the storage chamber 122, a piezoelectric driving element 129 is provided for each discharge unit. The piezoelectric driving element 129 of this embodiment includes a lower electrode 129a, an upper electrode 129c, and a piezoelectric body 129b sandwiched between these electrodes. The above-described control device supplies a drive voltage waveform to the piezoelectric drive element 129 in each of the plurality of discharge units U at a predetermined timing.

  When a drive voltage waveform is supplied to the piezoelectric drive element 129, the piezoelectric body 129b of the piezoelectric drive element 129 expands and contracts in the surface direction. As a result, the portion of the diaphragm 128 that overlaps the storage chamber 122 in a plane is displaced in the thickness direction perpendicular to the surface direction, and the volume of the storage chamber 122 changes. Further, when the diaphragm 128 is displaced, the needle 126 is also displaced toward the nozzle plate 121.

  As shown in FIG. 2C, the inner wall of the nozzle 125 of the present embodiment has a tapered surface 125a whose inner diameter increases toward the storage chamber 122 side. When the needle 126 is inserted through the nozzle 125, the tapered surface 125a comes into contact with the intermediate side wall 126b. Here, the entire inner wall of the nozzle 125 including the tapered surface 125a, the side wall 126b of the intermediate portion, and the side wall of the tip portion are wear-resistant coated.

  In the needle 126, the side wall 126a of the main part, the side wall 126b of the intermediate part, and the side wall of the tip part are subjected to lyophilic treatment, and have lyophilicity to the liquid material discharged from the discharge unit U. Further, an end face 126c facing the opening of the nozzle 125 is subjected to a liquid repellent treatment at the tip portion, and has a liquid repellent property with respect to the liquid material discharged from the discharge unit U.

Next, the discharge operation of the discharge unit U will be described with reference to FIGS. 3 (a) and 3 (b).
As shown in FIG. 3A, the storage chamber 122 is filled with the liquid material Q via the reservoir 124 and the supply path 123 before the liquid material is discharged from the discharge unit. The piezoelectric body 129b of the piezoelectric driving element 129 is in a discharged state, and the needle 126 is disposed at a position away from the nozzle 125 toward the piezoelectric driving element 129.

  In the piezoelectric driving element 129, when a voltage is applied between the lower electrode 129a and the upper electrode 129c, the piezoelectric body 129b is charged and contracts in the surface direction. As a result, as shown in FIG. 3B, the diaphragm 128 is bent so that the diaphragm 128 protrudes toward the storage chamber 122. As a result, the diaphragm 128 is displaced toward the storage chamber 122 and the needle 126 is inserted into the nozzle 125, and the volume of the storage chamber 122 is reduced and the liquid material Q corresponding to the volume reduction is processed from the nozzle 125. It is pushed out to the substrate W side.

  When the displacement amount of the diaphragm 128 is maximized, the needle 126 is fitted into the nozzle 125, and the liquid material Q in the reservoir 122 is separated from the portion of the liquid material pushed out of the nozzle 125. Further, since the end surface 126c of the needle 126 has liquid repellency with respect to the liquid material Q, the liquid material pushed out from the nozzle is separated from the end surface 126c and discharged from the nozzle 125 as a droplet Q1.

  As described above, in the droplet discharge head 12 of this embodiment, the liquid material pushed out from the nozzle 125 is favorably separated from the nozzle 125 side by the needle 126. Therefore, the discharged liquid material is prevented from continuing with the meniscus in the nozzle 125 (tailing), and flight bending due to tailing is prevented. Therefore, the landing error of the droplet Q due to the flight bend is reduced, and even a highly viscous liquid material can be arranged at a highly accurate position on the substrate W to be processed.

  Further, since tailing is prevented, distortion due to tailing is prevented from occurring in the meniscus in the nozzle 125 after ejection. Therefore, the shape of the meniscus can be controlled with high accuracy in the next discharge operation, and the liquid material can be discharged well from the nozzle 125.

  Further, unlike the method of applying vibration to the discharged liquid material, the momentum in the surface direction of the nozzle plate 121 is not given to the discharged liquid material, and thus flight bending may occur by separating the liquid material. Absent.

  Further, unlike the method of locally heating the liquid material in the vicinity of the nozzle, the liquid material in the meniscus is not dried by heating, and nozzle clogging does not occur. Further, since the needle 126 is accommodated on the storage chamber 122 side from the gas-liquid interface after the discharge operation, nozzle clogging due to drying of the liquid material on the surface of the needle 126 does not occur. As described above, in the droplet discharge head 12 of the present embodiment, nozzle clogging is significantly reduced, so that the droplet discharge head 12 can be stably discharged.

  In the above-described embodiment, the film forming apparatus for manufacturing the color filter is exemplified, but various devices other than the color filter can be applied to the film forming apparatus for manufacturing, the image printing apparatus, and the like. Further, in addition to a droplet discharge device using an ink jet method, the present invention can also be applied to a droplet discharge device or a dispenser using a thermal ink jet method. In any of the droplet discharge devices, when the liquid to be discharged is highly viscous to cause tailing, the effect can be obtained by applying the present invention.

  Further, although the side surface of the needle 126 is in contact with the inner wall of the nozzle 125, a configuration in which the needle does not contact (contact) with the inner wall of the nozzle may be adopted. Hereinafter, a modified example in which the shape of the needle is different from that of the embodiment will be described.

  4A and 4B are enlarged cross-sectional views of the tip end portion of the needle 126 and the nozzle 125 according to the first modification. FIG. 4B shows a state where the needle 126 of the first modification is inserted through the nozzle 125.

  As shown in FIG. 4A, the distal end portion of the needle 126 according to the first modification has a truncated cone shape whose diameter decreases from the main portion toward the end surface 126c. The side surface 126a and the side surface 126b are lyophilic with respect to the discharged liquid, and the end surface 126c is lyophobic.

  As shown in FIG. 4B, the needle 126 of the first modification is configured such that a part of the tip protrudes from the nozzle 125 toward the substrate to be processed W while being inserted through the nozzle 125. Further, there is a gap between the side face 126b and the inner wall of the nozzle 125 in the inserted state, and this gap is filled with a liquid material.

In a normal droplet discharge head, since the needle is not inserted into the nozzle, the liquid material discharged from the nozzle and the liquid material in the nozzle are connected by the entire cross section perpendicular to the axial direction of the nozzle.
On the other hand, in Modification 1, the liquid material discharged from the nozzle and the liquid material in the nozzle are connected only by the gap between the side surface 126 b and the inner wall of the nozzle 125. Therefore, the discharged liquid material and the liquid material in the nozzle are easily separated. As described above, even when a gap is provided between the side surface 126b and the inner wall of the nozzle 125, separation of the discharged liquid material can be promoted by imparting liquid repellency to the end surface 126c.

  Further, if the edge is provided between the end face 126c and the side wall 126b by making the center part of the tip part a concave part as in the second modification shown in FIG. 5, the discharged liquid material can be separated. Further promoted.

It is a schematic perspective view of the film-forming apparatus provided with the droplet discharge head of one Embodiment. (A) is a top view of a droplet discharge head, (b) is an A-A 'arrow sectional view in (a), and (c) is an enlarged view of a nozzle and a needle. (A), (b) is explanatory drawing which shows discharge operation of a discharge unit. (A), (b) is sectional drawing which shows schematic structure of the modification 1. As shown in FIG. 10 is a cross-sectional view showing a schematic configuration of Modification 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Film-forming apparatus, 12 ... Droplet discharge head (droplet discharge apparatus), 121 ... Nozzle plate, 122 ... Storage chamber, 125 ... Nozzle, 126 ... Needle, 127 ... Flow path forming substrate, 128 ... Vibration plate (wall surface of the storage chamber), 129 ... piezoelectric drive element, Q ... liquid, Q1 ... droplet, U ... discharge unit

Claims (5)

A nozzle plate with an open nozzle;
A flow path forming substrate provided on the nozzle plate and having a storage chamber, a reservoir, and a supply path;
A diaphragm having a needle provided on the flow path forming substrate and having a center aligned with the nozzle;
A piezoelectric driving element provided on the diaphragm and above the storage chamber, and comprising a lower electrode, a piezoelectric element, and an upper electrode;
The droplet discharge device according to claim 1, wherein a tip of the needle has an insertion portion that is inserted into the nozzle in a state where the needle comes down due to vertical vibration by the piezoelectric driving element.   2. The liquid droplet according to claim 1, wherein the insertion portion has an outer dimension of a cross section perpendicular to the axial direction of the nozzle that decreases toward an opening of the nozzle opposite to the storage chamber. Discharge device.   3. The droplet discharge device according to claim 1, wherein the insertion portion is inserted into the nozzle until a part of an axial side surface of the insertion portion comes into contact with an inner wall of the nozzle.   The droplet discharge device according to claim 3, wherein the side surface of the insertion portion is subjected to wear resistance treatment.   The insertion portion has an end surface facing an opening opposite to the storage chamber in the nozzle, and the side surface around the axial direction of the insertion portion is lyophilic with respect to the liquid material, and The droplet discharge device according to any one of claims 1 to 4, wherein an end surface is liquid repellent with respect to the liquid material.

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