JP2010253332A - Droplet discharge head and droplet discharge apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a droplet discharge head and a droplet discharge apparatus capable of equalizing the amount of droplets discharged by each nozzle and discharging by all the nozzles. <P>SOLUTION: The droplet discharge head 5 includes a pressure chamber 24 whose volume is changed by pressure generating means (vibration plates 20 and piezoelectric elements PZ) arranged corresponding to individual nozzles N, a common storage chamber 22 arranged in common with two or more nozzles N to store a functional liquid, and a supply passage 24a connecting the common storage chamber 22 with the pressure chamber 24. The supply passage 24a is arranged so that the flow resistance increases at both ends 5e in the arrangement direction of two or more nozzles N compared with that in the central part 5m. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a droplet discharge head and a droplet discharge device.

  2. Description of the Related Art Conventionally, a droplet discharge device (inkjet device) is known as a device for forming R (red), G (green), and B (blue) color filter layers on a color filter substrate for a display device, for example. This droplet discharge device includes a droplet discharge head in which a plurality of nozzles capable of discharging droplets by driving a piezoelectric element such as a piezo element are formed. A color filter layer is formed in the pixel region on the color filter substrate by discharging the droplet of the color filter material from the nozzle while scanning the droplet discharge head. (For example, refer to Patent Document 1).

JP 2003-159787 A

  However, the conventional droplet discharge device has a problem that the discharge amount of droplets by each nozzle of the droplet discharge head varies. For example, the amount of liquid droplets ejected from the nozzles is larger at the both ends of the droplet ejection head in the arrangement direction of the nozzles than at the center. Such variation in the discharge amount of the liquid droplets depending on the position of the nozzle is caused by, for example, the shape of a common storage chamber (ink reservoir) that stores functional liquid such as a color filter material discharged as liquid droplets. When variations occur in the discharge amount of droplets from each nozzle, a color filter layer having a uniform film thickness cannot be formed, causing display defects such as streak unevenness.

  In Patent Document 1, in order to suppress such variation in the discharge amount, droplets are not discharged from the nozzles located at both ends in the nozzle arrangement direction. Thereby, the dispersion | variation in discharge amount can be improved. However, if there is a nozzle that does not discharge, the drawing area of the droplet discharge head is reduced, and the productivity in forming a film such as a color filter is reduced.

  Therefore, the present invention provides a droplet discharge head and a droplet discharge device that can equalize the amount of droplets discharged from each nozzle and can discharge from all nozzles. .

  In order to solve the above problems, a droplet discharge head according to the present invention includes a plurality of nozzles that discharge functional liquid, and a pressure generating unit that is provided corresponding to each of the nozzles and discharges the functional liquid from the nozzle. A droplet discharge head having a pressure chamber provided corresponding to each of the nozzles, the pressure chamber of which pressure is changed by the pressure generating means, and the plurality of nozzles in common. A common storage chamber that stores the functional liquid, and a supply channel that communicates the common storage chamber and the pressure chamber, and the flow of the supply channel at both ends in the arrangement direction of the plurality of nozzles. The path resistance is provided so as to increase more than the channel resistance of the supply channel in the central portion.

With this configuration, when the drive element is driven and the diaphragm is vibrated by the drive element, the volume of the pressure chamber increases or decreases. When the volume of the pressure chamber increases, the pressure of the functional liquid stored in the pressure chamber decreases, and the functional liquid stored in the common storage chamber is supplied into the pressure chamber via the supply channel. Next, when the volume of the pressure chamber is reduced, the pressure in the pressure chamber is increased and the functional liquid droplet is ejected from the nozzle.
Here, since the cross-sectional area at both ends of the common storage chamber is smaller than that at the center, when the functional liquid flows into the pressure chamber, the flow rate of the functional liquid in the common storage chamber at both ends of the common storage chamber Will increase. Therefore, it becomes easier for the functional liquid to flow into the pressure chamber via the supply channel at both ends than the central portion of the common storage chamber.
However, the flow path resistance of the supply flow path at both ends of the common storage chamber is set to be larger than the flow path resistance of the common flow path at the center. Therefore, the functional liquid is less likely to flow into the pressure chamber via the common flow path at both ends than the central portion of the common storage chamber. That is, the increase in the inflow amount of the functional liquid into the pressure chamber due to the shape of the common storage chamber can be offset by the decrease in the inflow amount of the functional liquid into the pressure chamber due to the increase in the flow path resistance of the supply flow path. .
Therefore, regardless of the shape of the common storage chamber, the functional liquid can be made to uniformly flow into the pressure chamber corresponding to each nozzle, and the amount of liquid droplets discharged from each nozzle can be made uniform. Moreover, since the discharge amount of all the nozzles can be made uniform, the discharge can be performed from all the nozzles.

The droplet discharge head of the present invention is characterized in that a cross-sectional area of the supply flow path at the both end portions is smaller than a cross-sectional area of the supply flow path at the central portion.
Moreover, the droplet discharge head of the present invention is characterized in that the flow path length of the supply flow path at the both end portions is larger than the flow path length of the supply flow path at the central portion.
With this configuration, the flow path resistance of the supply flow path at both ends of the droplet discharge head can be made larger than the flow path resistance of the supply flow path at the center.

The width of the supply flow path at the both end portions is smaller than the width of the supply flow path at the central portion.
With this configuration, the flow path resistance of the supply flow path at both ends of the liquid drop discharge head can be easily determined from the flow path resistance of the supply flow path at the center using a normal method for manufacturing a liquid drop discharge head. Can also be increased.

In addition, a droplet discharge apparatus of the present invention includes any one of the droplet discharge heads described above.
With this configuration, regardless of the shape of the common storage chamber of the discharge head, the functional liquid is uniformly allowed to flow into the pressure chamber corresponding to each nozzle, and the amount of liquid droplets discharged from each nozzle is made uniform. be able to. Moreover, since the discharge amount of all the nozzles can be made uniform, the discharge can be performed from all the nozzles. Therefore, it is possible to prevent the productivity in forming a color filter or the like from being lowered without reducing the drawing area of the droplet discharge head.

1 is a perspective view showing a schematic configuration of a droplet discharge device in an embodiment of the present invention. 1 is a droplet discharge head according to an embodiment of the present invention, where (a) is a bottom view, (b) is a partially exploded perspective view, and (c) is a cross-sectional view. 3 is a graph showing the relationship between the width of a supply channel of the droplet discharge head shown in FIG. 2 and the droplet discharge amount. 3 is a graph showing a droplet discharge amount of each nozzle of the droplet discharge head shown in FIG. 2. It is a graph which shows the droplet discharge amount of each nozzle of the conventional droplet discharge head.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the scale is appropriately changed for each member so that each member has a size that can be recognized on the drawing. The droplet discharge device of this embodiment is a device that discharges droplets of a color filter material (functional liquid) onto a color filter substrate (droplet discharge target) by, for example, an inkjet method to form a color filter layer.

FIG. 1 is a perspective view showing a schematic configuration of a droplet discharge device IJ in the present embodiment.
As shown in FIG. 1, the droplet discharge device IJ includes an apparatus mount 1, a work stage 2, a stage moving device 3, a carriage 4, a droplet discharge head 5, a carriage moving device 6, a tube 7, a first tank 8, a first tank. Two tanks 9, a third tank 10, and a control device 11 are provided.

  Hereinafter, as shown in FIG. 1, an XYZ orthogonal coordinate system is set, and each member will be described with reference to the XYZ orthogonal coordinate system. The XYZ orthogonal coordinate system is set so that the X axis and the Y axis are parallel to the work stage 2, and the Z axis is set in a direction orthogonal to the work stage 2. Here, the work stage 2 is provided in parallel with the horizontal plane. That is, the X axis and the Y axis are parallel to the horizontal plane, and the Z axis is parallel to the vertical direction.

The apparatus base 1 is a support base that supports the work stage 2 and the stage moving device 3.
The work stage 2 is installed on the apparatus base 1 so as to be movable in the X-axis direction by a stage moving device 3. The work stage 2 is provided so as to hold the color filter substrate P transported from an upstream transport device (not shown) by a vacuum suction mechanism.

The stage moving device 3 includes a bearing mechanism such as a ball screw or a linear guide, and moves the work stage 2 in the X-axis direction based on a control signal input from the control device 11.
The carriage 4 is provided so as to hold the droplet discharge head 5, and is provided so as to be movable in the Y-axis direction and the Z-axis direction by the carriage moving device 6.

  The droplet discharge head 5 discharges droplets of color filter material based on drawing data and drive control signals input from the control device 11. The droplet discharge heads 5 are provided corresponding to the color filter materials R (red), G (green), and B (blue). A tube 7 is connected to each droplet discharge head 5 via a carriage 4.

  A tube 7 connected to the droplet discharge head 5 corresponding to R (red) is connected to a first tank 8 that stores a color filter material for R (red). A tube 7 connected to the droplet discharge head 5 corresponding to G (green) is connected to a second tank 9 that stores a color filter material for G (green). A tube 7 connected to the droplet discharge head 5 corresponding to B (blue) is connected to a third tank 10 that stores a color filter material for B (blue).

  As a result, the tube 7 from each of the first tank 8, the second tank 9, and the third tank 10 is attached to each of the droplet discharge heads 5 corresponding to R (red), G (green), and B (blue). Through these, color filter materials of R (red), G (green), and B (blue) are supplied.

  The carriage moving device 6 has a bridge structure straddling the device mount 1 and includes a bearing mechanism such as a ball screw or a linear guide in the Y-axis direction and the Z-axis direction. The carriage moving device 6 moves the carriage 4 in the Y-axis direction and the Z-axis direction based on a control signal input from the control device 11.

  The control device 11 is configured to output a stage position indicating the X coordinate of the work stage 2 to the stage moving device 3 as a control signal. In addition, a carriage position indicating the Y coordinate and Z coordinate of the carriage 4 is output to the carriage moving device 6. In addition, drawing data and a drive control signal are output to a drive circuit board (not shown) of the droplet discharge head 5.

  FIG. 2A is a bottom view of one droplet discharge head 5. FIG. 2B is a perspective view showing one droplet discharge head 5 partially cut. FIG. 2C is a cross-sectional view of one droplet discharge head 5 along the arrangement direction (Y direction) of the nozzles N shown in FIG.

As shown in FIGS. 2A to 2C, the droplet discharge head 5 includes a nozzle plate 21, a partition member 23, a vibration plate 20, and a piezoelectric element PZ (pressure generating means).
As shown in FIG. 2A, the nozzle plate 21 includes a plurality of (for example, 180) nozzles N arranged in a line in the arrangement direction parallel to the long side direction (Y axis) of the rectangular nozzle plate 21. Is formed. The nozzle N is formed so as to penetrate the nozzle plate 21 as shown in FIG.

  The partition member 23 is joined to the nozzle plate 21 as shown in FIGS. 2B and 2C, and has a common storage chamber (reservoir) 22, a pressure chamber (cavity) 24, and a supply flow path 24a. It is partitioned. The partition member 23 is formed, for example, by etching a silicon substrate and selectively removing portions corresponding to the common storage chamber 22, the pressure chamber 24, and the supply flow path 24a. The diaphragm 20 is joined to the partition wall member 23 so as to seal the upper part of the common storage chamber 22, the pressure chamber 24, and the supply flow path 24a.

  Thereby, the common storage chamber 22 and the pressure chamber 24 are surrounded by the nozzle plate 21, the partition member 23, and the vibration plate 20 so as to store the color filter material. Similarly, the supply flow path 24 a is surrounded by the nozzle plate 21, the partition wall member 23, and the vibration plate 20, and is formed as a flow path for supplying the color filter material stored in the common storage chamber 22 to each pressure chamber 24. Yes.

  On the vibration plate 20, piezoelectric elements (drive elements) PZ are arranged corresponding to the respective pressure chambers 24. The piezoelectric element PZ is, for example, a piezoelectric element, and includes a piezoelectric material 25 sandwiched between a pair of electrodes 26 as shown in FIG. In the piezoelectric element PZ, the piezoelectric material 25 contracts in accordance with a voltage waveform supplied from a drive circuit board (not shown) to the pair of electrodes 26 so that the diaphragm 20 vibrates in the pressure chamber 24 direction (Z-axis direction). It has become. Further, the diaphragm 20 has a supply port 20a to which the tube 7 shown in FIG.

  The common storage chamber 22 is provided in common to the plurality of nozzles N, and stores the color filter material supplied to the droplet discharge head 5 via the tube 7 shown in FIG. The common storage chamber 22 is formed in a trapezoidal shape as viewed from the Z-axis direction (vertical direction) as shown in FIG. Therefore, the cross-sectional area along the X axis of the common storage chamber 22 at both end portions 5 e and 5 e in the arrangement direction of the nozzles N of the droplet discharge head 5 is the X axis of the common storage chamber 22 at the central portion 5 m of the droplet discharge head 5. It is smaller than the cross-sectional area along

  The pressure chamber 24 is provided corresponding to each nozzle N, and stores the color filter material supplied from the common storage chamber 22 via the supply flow path 24a. The volume of the pressure chamber 24 changes due to the vibration of the diaphragm 20.

  The supply flow path 24 a is a flow path that connects the common storage chamber 22 and each of the pressure chambers 24. In the present embodiment, the both ends 5e and 5e in the arrangement direction of the nozzles N of the droplet discharge head 5 shown in FIG. 2A are provided so that the flow path resistance of the supply flow path 24a is larger than the central part 5m. It has been. That is, the flow path resistance of the supply flow path 24a is increased in accordance with the decrease in the cross-sectional area of the common storage chamber 22. Specifically, as shown in FIG. 2B, the flow path resistance is increased or decreased by adjusting the width W, height H, and flow path length FL of the supply flow path 24a.

  In the present embodiment, the width W of the supply flow path 24a in the direction along the long side direction of the nozzle plate 21 (the arrangement direction of the nozzles N) is reduced according to the reduction in the cross-sectional area of the common storage chamber 22. Thereby, the cross-sectional area of the supply flow path 24a in the both ends 5e and 5e of the droplet discharge head 5 is smaller than the cross-sectional area of the supply flow path 24a in the center part 5m. Moreover, the cross-sectional area of the supply flow path 24a becomes smaller as it approaches the both ends 5e, 5e of the droplet discharge head 5.

  When forming a color filter layer on the color filter substrate P by the droplet discharge device IJ shown in FIG. 1, first, each droplet discharge head 5 from the first tank 8 to the third tank 10 through the tube 7 is used. Supply color filter material. The color filter material supplied from the first tank 8 to the third tank 10 to each droplet discharge head 5 is introduced into the common storage chamber 22 from the supply port 20a shown in FIG. The color filter material filling the common storage chamber 22 is introduced into each of the pressure chambers 24 via the supply flow path 24a. Thereby, the common storage chamber 22 and the pressure chamber 24 of the droplet discharge head 5 are filled with the color filter material.

  Further, the color filter substrate P is held on the work stage 2, a control signal is output to the stage moving device 3 by the control device 11, and the stage moving device 3 is driven to bring the work stage 2 to a predetermined position in the X-axis direction. Move. Further, the control device 11 outputs a control signal to the carriage moving device 6 and drives the carriage moving device 6 to move the carriage 4 to predetermined positions in the Y-axis direction and the Z-axis direction.

  When the carriage 4 reaches a predetermined position on the color filter substrate P, the control device 11 outputs drawing data and a drive control signal to a drive circuit substrate (not shown) of the droplet discharge head 5. The drive circuit board supplies a voltage waveform to the piezoelectric element PZ based on the input drive control signal. The piezoelectric element PZ contracts according to the input voltage waveform, and deforms the diaphragm 20 so as to bulge in the direction opposite to the pressure chamber 24 (Z-axis direction). Then, the volume of the pressure chamber 24 increases and the pressure in the pressure chamber 24 decreases. As a result, the color filter material flows from the common storage chamber 22 into the pressure chamber 24.

  Next, the shape returns to the original shape according to the voltage waveform supplied with the piezoelectric element PZ, and the diaphragm deformed in the direction opposite to the pressure chamber 24 returns to the original shape. Thereby, the volume of the pressure chamber 24 decreases and the pressure in the pressure chamber 24 increases. Then, a droplet L of the color filter material is discharged from the nozzle N. The droplets L ejected from the plurality of nozzles N land on a predetermined region on the color filter substrate P shown in FIG. 1, and a color filter layer is formed on the color filter substrate P.

  Here, as shown in FIG. 2A, the common storage chamber 22 is formed in a trapezoidal shape having a cross-sectional area smaller than that of the central portion 5m at both ends 5e, 5e of the droplet discharge head 5. Therefore, when the color filter material flows into the pressure chamber 24, the flow rate of the color filter material increases at both ends 5e, 5e of the droplet discharge head 5. As the flow rate of the color filter material increases, the color filter material easily flows into the pressure chamber 24 via the supply flow path 24a.

FIG. 5 is a graph showing the relationship between the position of a nozzle of a droplet discharge device equipped with a conventional droplet discharge head and the droplet discharge amount. The horizontal axis represents the position of the nozzles of the droplet discharge head in the arrangement direction, and the vertical axis represents the droplet discharge amount.
As shown in FIG. 5, in the conventional droplet discharge device, the flow rate of the color filter material is increased at both ends of the droplet discharge head, and as a result, a large amount of color filter material flows into the pressure chambers at both ends. The droplet discharge amount at both ends of the discharge head was larger than the droplet discharge amount at the center.

  On the other hand, in the droplet discharge head 5 of the present embodiment, the width W of the supply flow path 24a is reduced in accordance with the reduction in the cross-sectional area of the common storage chamber 22. Thereby, the cross-sectional area of the supply flow path 24a in both ends 5e and 5e of the droplet discharge head 5 is made smaller than the cross-sectional area of the supply flow path 24a in the central part 5m. Moreover, the cross-sectional area of the supply flow path 24a becomes smaller as it approaches the both ends 5e, 5e of the droplet discharge head 5. Thereby, the flow path resistance of the supply flow path 24e is increased at both ends 5e, 5e in the arrangement direction of the nozzles N of the droplet discharge head 5 shown in FIG. .

FIG. 3 is a graph showing the relationship between the width W of the supply flow path 24a and the discharge amount of the droplet L.
As shown in FIG. 3, the width W of the supply flow path 24a and the discharge amount of the droplet L have a proportional relationship that can be approximated by a straight line. In the present embodiment, by using the proportional relationship between the width W of the supply flow path 24a and the discharge amount of the droplets L, the discharge amount of the droplets L from the respective nozzles N is made uniform. The width W of the supply flow path 24a corresponding to the nozzle N is determined.

  In the present embodiment, the flow path resistance of the supply flow path 24a at both ends 5e, 5e of the droplet discharge head 5 is provided to be larger than the flow path resistance of the supply flow path 24a of the central part 5m. Therefore, the color filter material is less likely to flow into the pressure chamber 24 via the supply flow path 24a at both ends 5e and 5e than at the central portion 5m of the droplet discharge head 5. That is, an increase in the amount of color filter material flowing into the pressure chamber 24 due to the shape of the common storage chamber 22 is a decrease in the amount of color filter material flowing into the pressure chamber 24 due to an increase in channel resistance of the supply channel 24a. Can be offset.

FIG. 4 is a graph showing the relationship between the position of the nozzle N of the droplet discharge device IJ of this embodiment and the discharge amount of the droplet L. The horizontal axis represents the position in the arrangement direction of the nozzles N of the droplet discharge head 5, and the vertical axis represents the discharge amount of the droplet L.
As shown in FIG. 4, according to the droplet discharge device IJ of this embodiment, the color filter material is caused to flow uniformly into the pressure chambers 24 corresponding to the nozzles N regardless of the shape of the common storage chamber 22. The amount of droplets L discharged from the nozzle N can be made uniform. In addition, since the discharge amount of the droplets L of all the nozzles N can be made uniform, the discharge can be performed from all the nozzles N.

  In the present embodiment, the flow path resistance of the supply flow path 24a is adjusted by adjusting the width W of the supply flow path 24a in accordance with the reduction in the cross-sectional area of the common storage chamber 22. Therefore, the flow path resistance of the supply flow path 24a at both ends 5e, 5e of the droplet discharge head 5 can be easily set to the flow path resistance of the supply flow path 24a at the central part 5m by a normal manufacturing method such as photolithography and etching. Can be larger.

  As described above, according to the droplet discharge head 5 and the droplet discharge device IJ of the present embodiment, the amount of the droplet L discharged from each nozzle N can be made uniform, and all the nozzles N Can be discharged. Therefore, it is possible to prevent the productivity in forming the color filter from being lowered without reducing the drawing area of the droplet discharge head 5.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, a configuration other than the piezoelectric element and the diaphragm may be used as the pressure generating unit. The present invention can also be applied to, for example, a droplet discharge head and a droplet discharge device provided with a pressure generating unit that changes the pressure in a pressure chamber by generating bubbles by heating a functional liquid.
Further, the channel resistance of the supply channel 24a may be adjusted by adjusting the channel length of the supply channel 24a or adjusting the height of the supply channel 24a. Moreover, you may adjust the flow path resistance of the supply flow path 24a combining these.
Further, the shape of the common storage chamber is not limited to the shape and arrangement shown in FIG. For example, the upper and lower sides of the trapezoidal common storage chamber may be reversed to increase the length of the supply flow path at both ends of the droplet discharge head.

5 droplet discharge head, 5e end, 5m center, 20 diaphragm (pressure generating means), 22 common storage chamber, 24 pressure chamber, 24a supply channel, FL channel length, IJ droplet discharge device, N nozzle , PZ piezoelectric element (pressure generating means), W width

Claims (5)

A liquid droplet ejection head having a plurality of nozzles for ejecting a functional liquid, and a pressure generating unit that is provided corresponding to each of the nozzles and ejects the functional liquid from the nozzle,
The droplet discharge head is provided corresponding to each of the nozzles, and a pressure chamber whose pressure is changed by the pressure generating means; a common storage chamber that is provided in common for the plurality of nozzles and stores the functional liquid; A supply flow path communicating the common storage chamber and the pressure chamber,
The liquid droplet ejection, wherein the flow path resistance of the supply flow path at both ends in the arrangement direction of the plurality of nozzles is set to be larger than the flow path resistance of the supply flow path at the central portion. apparatus. 2. The droplet discharge head according to claim 1, wherein a cross-sectional area of the supply flow path at the both end portions is smaller than a cross-sectional area of the supply flow path at the central portion. 3. The droplet discharge head according to claim 1, wherein a flow path length of the supply flow path at the both end portions is larger than a flow path length of the supply flow path at the central portion. 4. The droplet discharge head according to claim 1, wherein a width of the supply flow path at the both end portions is smaller than a width of the supply flow path at the central portion. 5. A droplet discharge apparatus comprising the droplet discharge head according to claim 1.

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