JP6119998B2 - Electrostatic coating method and electrostatic coating device - Google Patents

Description

  The present invention relates to an electrostatic coating method in which various liquids are stretched thinly from an end of a nozzle with an electric force to form a fine pattern on a substrate.

2. Description of the Related Art Conventionally, as a method for forming fine droplets and applying a fine pattern on a substrate, a method using electrostatic attraction as described in Patent Document 1, for example, is known.
FIG. 12 shows the method of Patent Document 1.

  In this method, the nozzle 2 is disposed so as to face the surface of the application object 4, and a pulse voltage is applied between the application object 4 and the nozzle 2 from the power supply unit 30 to electrostatically discharge the liquid 1 at the nozzle tip 3. The droplet 31 is dropped on the coating object 4 by being sucked by the force toward the coating object 4 side.

  Although patent document 2 is not application | coating to an application | coating target object, the method of discharging the micro droplet which has a uniform particle size in a solution using a needle is also known. In patent document 2, the electrostatic force like patent document 1 is not used.

JP 2001-038911 A JP 2006-320795 A

When the solution attached to the tip of the needle is applied to the application object using the technique of Patent Document 2, the following occurs.
As shown in FIG. 13A, the needle 32 disposed in the nozzle 2 is lowered until the tip protrudes from the nozzle tip 3 as shown in FIG. 13B. At this time, a very small amount of the liquid 1 droplet 33 in the nozzle 2 is attached to the tip of the needle 32. Thereafter, as shown in FIG. 13C, the needle 32 is lowered until the droplet 33 attached to the tip contacts the application target 4. Thereby, the droplet 33 attached to the tip of the needle 32 can be applied to the application target 4.

  However, in the conventional method shown in FIG. 12 and the conceivable method shown in FIG. 13, when a fine linear pattern is formed on the surface of the coating object 4 by coating, the edge linearity of the coating result is poor, and the pattern There is a problem that uniform application of the width cannot be realized.

The application state in this case is shown in FIG.
FIG. 14A shows a state immediately after the minute droplets are continuously applied. FIG. 14B shows a state where drying of the applied droplets is completed. Thus, although the leveling of adjacent droplets progresses in the drying stage after coating, since traces applied as droplets remain, it becomes difficult to obtain edge linearity. This is because the discharged fine droplets have a large surface area, and drying is promoted before reaching the application target 4 after being discharged from the nozzle 2, so that it becomes difficult to level after reaching the application target 4. It is.

  For this reason, in order to achieve a high edge linearity and uniform pattern width application, it is desirable to apply the liquid continuously without interrupting the liquid droplets, rather than joining the liquid droplets together. Conceivable.

  Therefore, a liquid reservoir 34 is formed at the tip of the nozzle 2 as shown in FIG. 15 while utilizing the principle of sucking droplets by electrostatic force, and the liquid 1 can be continuously applied to the surface of the application target 4. Although it is conceivable, when continuous application is performed by the liquid reservoir 34, it takes time to form the start and end of the application accompanying expansion and contraction of the liquid reservoir 34 due to electrostatic force, so that the tact time is increased and the application state is disturbed. There is a problem that it is easy.

FIGS. 16A to 16D show the formation state of the liquid reservoir 34 at the application start end when the liquid 1 is continuously applied by the liquid reservoir 8.
FIG. 16A shows a state before voltage application to the nozzle 2 containing the liquid 1.

  Next, when a voltage is applied between the nozzle 2 and the coating object 4, as shown in FIGS. 16 (b) and 16 (c), the liquid reservoir 34 extends toward the coating object 4 by electrostatic force, and FIG. 16 (c). As shown in FIG. 16D, the liquid pool 34 finally reaches the coating target 4 as shown in FIG. 16D after passing through the unstable liquid pool 34 before reaching the coating target 4.

  In such suction by electrostatic force, since it takes time to shift from the unstable state of FIG. 16C to the stable state of FIG. 16D, the nozzle 2 for coating and the coating object 4 It becomes very difficult to control the timing of starting the relative movement of the liquid and the position at which the liquid reservoir 34 reaches the application target 4 is different from the target. As a result, as shown in FIG. 17 (a), an excessive amount of the liquid 1 is applied to the application start end, resulting in a thickening 35 in the line width, and conversely as shown in FIG. 17 (b). There is a problem that the application amount of the liquid 1 is insufficient and a break 36 occurs.

FIGS. 18A to 18D show a reduced state of the liquid reservoir 34 at the application end.
As described above, the residual charge held by the liquid reservoir 34 immediately after the voltage application is stopped (FIG. 18B) as compared to before the voltage application is stopped to the nozzle 2 containing the liquid 1 (FIG. 18A). Under the influence of the above, the liquid reservoir 34 is finally separated as shown in FIGS. 18C and 18D through a state where it is not immediately separated from the application object 4 but is held unstable.

  In such suction by electrostatic force, since the unstable state of FIG. 18B continues even after the application of voltage is stopped, the relative relationship between the nozzle 2 and the application object 4 for finishing the application is continued. The timing control for stopping the movement becomes very difficult, and the position at which the liquid reservoir 34 is separated from the application target 4 is different from the target. As a result, as shown in FIG. 19 (a), an excessive amount of liquid 1 is applied to the end of application, resulting in a thickening 35 in the line width, and conversely, as shown in FIG. 19 (b). There is a problem in that the application amount of the liquid 1 is insufficient and a break 36 occurs.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electrostatic coating method that does not require time for formation of the start and end points, does not disturb the shape, has high edge linearity, and realizes uniform pattern width coating.

In the electrostatic coating method of the present invention, a nozzle tip of a nozzle containing a liquid is disposed so as to face an object to be coated, and a potential difference is applied between the liquid and the object to be coated at the time of coating to the nozzle tip. A liquid reservoir extending toward the application object side is formed, and at the time of application, the tip of the needle disposed in the nozzle is moved from the retracted position to the advanced position to move the tip of the needle A state in which the tip of the liquid pool is brought into contact with the object to be coated, the tip of the liquid pool is brought into contact with the object to be coated, and then the tip of the needle is projected from the nozzle. the object to be coated and the nozzle is relatively moved in the horizontal direction, it characterized that you continuously applying the liquid to the object to be coated in.

The electrostatic coating apparatus of the present invention is an electrostatic coating apparatus that applies a potential difference between a liquid in a nozzle and an application target to draw the liquid from the nozzle and apply the liquid to the application target. And a power supply unit that applies a predetermined voltage between the application target, a needle that can move up and down in the nozzle, a needle drive unit that drives the needle up and down, and the application target at the tip of the nozzle during application The power supply unit is controlled so as to form a liquid pool of liquid that extends toward the object side, and the tip of the needle is moved from the retracted position to the advanced position so that the tip of the needle becomes the liquid pool. driving the needle driving unit so as to protrude, after the leading end of the liquid reservoir is brought into contact with the object to be coated, the coating of the tip of the needle in a state of protruding from the nozzle Relatively moving the nozzle and the object in the horizontal direction, and having a said coating you continuously applying the liquid to the object control unit.

  According to the electrostatic coating method of the present invention, a potential difference is applied to form a liquid reservoir extending toward the object to be coated at the tip of the nozzle, and the tip of a needle disposed in the nozzle projects into the liquid reservoir. Since the tip of the liquid reservoir is brought into contact with the object to be applied, the responsiveness of the liquid reservoir at the nozzle tip can be improved, disturbance at the start and end of application can be prevented, and the tact time can be shortened. it can. Furthermore, since a liquid can be continuously applied, a highly linear pattern can be formed accurately.

Schematic of an electrostatic coating apparatus in an embodiment of the present invention (A)-(c) is the application | coating flow figure in the application | coating start end in the embodiment (A)-(c) The application | coating flow figure in the application | coating termination | terminus in the embodiment The expanded sectional view in the case of condition 1 of the nozzle tip of the electrostatic coating device in the embodiment Enlarged view showing needle contact angles θ1 to θ3 in condition 1 Explanatory drawing of the application result of Condition 1 to Condition 8 of the present invention The expanded sectional view in the case of condition 3 of the nozzle tip of the electrostatic coating device in the embodiment Enlarged view showing needle contact angles θ4 and θ5 under condition 3 The expanded sectional view in the case of condition 5 of the nozzle tip of the electrostatic coating device in the embodiment The expanded sectional view in the case of condition 7 of the nozzle tip of the electrostatic coating device in the embodiment Enlarged view showing needle contact angles θ6 and θ7 under condition 7 Explanatory drawing of patent document 1 by electrostatic attraction by pulse voltage (A) to (c) are application flow charts in reference to Patent Document 2. (A) (b) is explanatory drawing of the problem at the time of apply | coating with the application | coating flow of FIG. The figure of the continuous application state by the liquid pool extended by the electrostatic force by patent document 1 (A)-(d) is a figure of the liquid pool formation state in the application start end by the liquid pool of patent document 1 (A) (b) is a top view of application failure by the application start end by patent documents 1 (A)-(d) is the figure of the liquid pool formation state in the application | coating termination | terminus by patent document 1. FIG. (A) (b) is a top view of application failure in application termination by patent documents 1

Hereinafter, the electrostatic coating method of the present invention will be described based on the electrostatic coating apparatus of the embodiment.
1 to 3 show an electrostatic coating apparatus for realizing the electrostatic coating method of the present invention.
In FIG. 1, the electrostatic coating apparatus is configured as follows.

  The nozzle 2 containing the liquid 1 is disposed with the nozzle tip 3 facing the application target 4. A voltage is applied between the liquid 1 and the application object 4 by the power supply unit 5. Inside the nozzle 2, a needle 6 that can move up and down is arranged. The liquid 1 is supplied from the liquid supply unit 7 into the nozzle 2.

  In addition, when using the nozzle 2 formed of an insulating material, since a voltage cannot be applied through the nozzle 2, an electrode plate 8 that contacts the liquid 1 inside the nozzle 2 is provided, and the electrode plate 8 A voltage is applied from the power supply unit 5. When the nozzle 2 is formed of a conductive material, a voltage can be applied through the nozzle 2, so that the electrode plate 8 may be omitted.

The nozzle 2 is held by the nozzle drive unit 9 and the movement control of the vertical position with respect to the application target 4 is performed.
The needle 6 is held by the needle drive unit 10 and its vertical position is controlled.

The stage 11 is position-controlled by a stage drive unit 12 that holds the application object 4 by suction and moves the application object 4 in the horizontal direction during application.
A voltage is applied between the application object 4 and the liquid 1 contained in the nozzle 2 by the power supply unit 5. The operation of the nozzle drive unit 9, the needle drive unit 10, and the stage drive unit 12 is controlled by the control unit 13.

  The stage driving unit 12 is provided to relatively move the nozzle 2 and the coating object 4 in the horizontal direction during application, but a nozzle horizontal driving unit (not shown) that moves the nozzle 2 in the horizontal direction; It is also possible to provide at least one of the stage driving units 12 and relatively move the nozzle 2 and the coating object 4 in the horizontal direction during coating.

  2A to 2C show application flow diagrams at the application start end. 2A shows a state before voltage application at the coating start end, FIG. 2B shows a state immediately after voltage application at the coating start end, and FIG. 2C shows a time when the liquid reaches the coating target at the coating start end. FIG. 3A shows a steady application at the application end, FIG. 3B shows the needle rising at the application end, and FIG. 3C shows a completion of needle movement at the application end.

This will be described based on this application flow.
In FIG. 2A, the application object 4 is placed on the stage 11, and the nozzle 2 is aligned with the application start position. At this time, the position of the tip of the needle 6 is controlled by the needle drive unit 10 so as to be positioned inside the nozzle 2 rather than the nozzle tip 3.

Next, the height of the nozzle 2 is controlled by the nozzle drive unit 9 so that the gap between the nozzle tip 3 and the coating object 4 becomes a desired distance.
In FIG. 2B and FIG. 2C, a voltage is applied between the liquid 1 and the application object 4 by the power supply unit 5 and the needle 6 is moved to the application object 4 side by the needle drive unit 10. Is lowered until it reaches a desired position on the side of the application object 4 with respect to the nozzle tip 3.

  Thereby, in addition to the liquid 1 being sucked by the electrostatic force toward the application target 4, the center of the liquid reservoir 14 at the nozzle tip 3 is selectively applied to the application target 4 side as the needle 6 descends. Thus, it is possible to greatly shorten the time during which the liquid reservoir 14 is in an unstable state before reaching the coating object 4 in the process of extending the liquid reservoir 14 toward the coating object 4.

  As a result, timing control for starting relative movement between the nozzle 2 for application and the application object 4 is facilitated, and the position at which the liquid reservoir 14 reaches the application object 4 can be landed as intended. Become. Thereby, the effect that precise application | coating can be implement | achieved is obtained, without the thickening of a line | wire width and a discontinuity occurring also in the application | coating start end. In addition, since the time required for coating at the start end can be shortened, an effect that the production tact can be shortened can be obtained.

Thereafter, after the thinly stretched liquid reservoir 14 reaches the application target 4, the nozzle 2 and the application target 4 are relatively moved in the horizontal direction at a desired timing and applied.
In this case, the timing at which the relative movement between the nozzle 2 and the coating object 4 is started can be easily reproduced by confirming in advance experiments. This is because the liquid reservoir 14 extends toward the application target 4 by selectively extending the central portion of the liquid reservoir 14 at the nozzle tip 3 toward the application target 4 by the lowering of the needle 6. This is because the time in the unstable state before reaching 4 can be greatly shortened.

  From the state of FIG. 3A applied in a steady state to the application end position, as shown in FIGS. 3B and 3C, the liquid 1 and the application object 4 are applied by the power source unit 5 at a desired timing. The voltage applied in the meantime is stopped, and the needle 6 is raised toward the nozzle 2 until the tip reaches a desired position inside the nozzle tip 3.

  Thus, as the needle 6 is raised, the central portion of the liquid reservoir 14 at the nozzle tip 3 can be selectively pulled back to the nozzle 2 side, and the residual retained by the liquid reservoir 14 immediately after the voltage application is stopped. It is possible to greatly reduce the time during which the coating object 4 is not separated from the coating object 4 due to the influence of electric charges and is kept unstable. As a result, the timing control for stopping the relative movement between the nozzle 2 and the application target 4 for ending application is facilitated, and the position at which the liquid reservoir 14 is separated from the application target 4 becomes as intended. .

  As a result, even at the end of application, there is an effect that precise application can be realized without causing an increase in line width or interruption. In addition, since the time required for coating at the end can be shortened, an effect that the production tact can be shortened can be obtained.

  In this case, the timing of stopping the power supply unit 5 and raising the needle 6 can be easily reproduced by confirming in advance experiments. This is because the central portion of the liquid reservoir 14 at the nozzle tip 3 can be selectively pulled back to the nozzle 2 side by raising the needle 6, and the residual charge held by the liquid reservoir 14 immediately after the voltage application is stopped. This is because the time that is not separated from the application object 4 due to the influence and is kept unstable can be greatly shortened.

  As described above, according to the present invention, the responsiveness of the liquid pool at the tip of the nozzle can be improved by the vertical movement of the needle 6, the disturbance at the start and end of application can be prevented, and the tact time can be shortened. realizable. Furthermore, since a liquid can be continuously applied, a highly linear pattern can be formed accurately.

Based on Conditions 1 to 8, the above electrostatic coating apparatus will be described in detail.
− Condition 1 −
Application of a fine linear pattern was performed using the electrostatic coating apparatus shown in FIG. The details of Condition 1 are as follows.

  Here, the nozzle 2 is made of glass and has a tip inner diameter 15 of 200 μm as shown in FIG. As the liquid 1, nano Ag ink 16 having a central particle diameter of 200 nm was used. The nano Ag ink used was a solid content concentration of 80 wt% and the ink viscosity was 1500 mPa · s. The needle 6 was made of tungsten, and a constant round bar having a diameter 17 of 50 μm was used. A glass substrate having a thickness of 1.7 mm was used as the coating object 4. The distance between the nozzle tip surface 18 and the coating object 4 was 400 μm. As shown in FIG. 5, the contact angle θ 1 of the nano Ag ink 16 on the nozzle tip surface 18 is 20 °, the contact angle θ 2 of the nano Ag ink 16 on the needle side surface 16 is 15 °, and the contact of the nano Ag ink 16 on the needle tip 19. The angle θ3 was 15 °.

  When not applied, the needle tip surface 19 is held at a position of 500 μm from the nozzle tip surface 18 toward the inside of the nozzle 2, and at the time of coating, the needle tip is positioned at a position of 200 μm from the nozzle tip surface 18 toward the application target 4. Surface 19 was held. Here, the gap 21 between the inner wall of the nozzle 2 and the needle side surface 20 on the nozzle tip surface 18 is 75 μm, which is larger than 50 μm of the diameter 17 of the needle 6. The moving speed of the needle 6 was 15 mm / s, and the power supply unit 5 applied a DC voltage of 1.5 kV. At this time, the nozzle 2 side was set to +.

  At the application start end, the needle 6 started to descend simultaneously with the application of voltage, and the relative movement (velocity 50 mm / s) of the nozzle 2 and the application object 4 was started 100 ms after the voltage application. At the end of application, voltage application was stopped 100 ms before reaching the application end position, and the needle 6 started to rise. The rising speed at that time was 15 mm / s.

  In this way, 30 coatings having a line width of 8 μm, a coating thickness of 0.5 μm, and a coating length of 100 mm were formed, and the states of the coating start end and the coating end within a range of 20 mm from the coating end were evaluated. The result is shown in FIG.

Note that the evaluation index of the line width at the start and end in FIG. 6 is “◯” if all the samples are in the range of 8 μm ± 3%, and “X” if there is a sample that is not even in one place. With respect to the interruption, it was evaluated as “◯” if there was no interruption in all the samples, and “x” if interruption occurred even at one location. With respect to the application position accuracy at the start and end, the position deviation amount with respect to the target position was evaluated as “◯” if it was within 100 μm for all the samples, and “X” if there was a deviation exceeding 100 μm even at one location. For line widths at the start and end,
If all samples are in the range of 8μm ± 2.8%
If all samples are in the range of 8μm ± 2.5%
If all samples are in the range of 8μm ± 2.3%
If all samples are in the range of 8μm ± 2.0% ○○○○○
It was. FIG. 6 also shows the results of evaluation performed on conditions 2 to 8 described later and Comparative Example 1 based on the same criteria as in Condition 1.

− Comparative Example 1 −
As Comparative Example 1, coating was performed by a method involving expansion and contraction of a liquid reservoir only by an electrostatic force according to the conventional method shown in FIG.

  The nozzle 2 of this comparative example 1 was made of glass and had an inner diameter of 200 μm at the nozzle tip. As the liquid 1, nano Ag ink having a central particle diameter of 200 nm was used. The nano Ag ink used was a solid content concentration of 80 wt% and the ink viscosity was 1500 mPa · s. As the coating object 4, a glass substrate having a thickness of 1.7 mm was used. The distance between the nozzle tip surface and the coating object 4 was 400 μm. The contact angle θ1 of the nano Ag ink at the nozzle tip surface was 20 °. The power supply unit 5 applied a DC voltage of 1.5 kV (+ on the nozzle side). At the coating start end, relative movement (speed 50 mm / s) between the nozzle 2 and the coating object 4 was started 100 ms after voltage application. At the end of application, voltage application was stopped 100 ms before reaching the application end position.

  In the electrostatic coating of Comparative Example 1 according to the conventional method, the liquid reservoir 14 extends toward the coating object 4 due to electrostatic force immediately after the voltage application, and the liquid reservoir 14 before reaching the coating object 4 is not applied. Through a stable state, the liquid reservoir 14 finally reaches the application target 4. In the suction by the conventional electrostatic force, since it takes time to shift from the unstable state before the liquid reservoir 14 reaches the application target 4 to the stable state, the relative relationship between the nozzle 2 for application and the application target 4 is relatively long. As a result, it is very difficult to control the timing for starting the movement, and the position at which the liquid reservoir 14 reaches the application target 4 is different from the target. As a result, a problem arises in that an unnecessarily large amount is applied to the starting end of the coating and the line width becomes thick, or conversely, the coating amount is insufficient and is interrupted.

  At the end of application, even after the application of voltage is stopped, due to the influence of the residual charge held by the liquid reservoir 14, the liquid is not separated immediately from the application object 4 but is held unstable, and finally the liquid is supplied. The reservoir 14 was cut off. In this way, in the conventional suction by electrostatic force, an unstable state continues even after the voltage application is stopped, and therefore, timing control for stopping the relative movement between the nozzle 2 and the coating object 4 for finishing the coating. As a result, the position where the liquid reservoir 14 is separated from the coating object 4 is different from the target. As a result, a more amount than necessary was applied to the application end, resulting in a problem that the line width was thickened, or conversely, the application amount was insufficient, leading to interruptions.

  On the other hand, under the condition 1, as the needle 6 descends at the application start end, the central portion of the liquid reservoir 14 at the nozzle tip can be selectively extended to the application object 4 side. It is possible to greatly reduce the time that is an unstable state before reaching the coating object 4 in the process of extending toward the coating object 4 side. As a result, timing control for starting relative movement between the nozzle 2 for application and the application object 4 is facilitated, and the position at which the liquid reservoir 14 reaches the application object 4 can be landed as intended. Become. As a result, precise coating could be realized without increasing the line width or interruption at the coating start end.

In addition, since the time required for coating at the starting end can be shortened, production tact can be shortened.
Further, since the contact angle θ1 of the nano Ag ink 16 on the nozzle tip surface 18 is larger than the contact angle θ2 on the needle side surface 20 and the contact angle θ3 on the needle tip surface 19, it is pulled out from the nozzle 2 due to electrostatic force and the needle 6 descending. Thus, the liquid reservoir 14 can be prevented from spreading on the nozzle tip surface 18, and the liquid reservoir 14 can be held on the needle tip surface 19. As a result, the expansion and contraction of the liquid reservoir 14 can be speeded up, and stable continuous application can be realized without the liquid reservoir 14 being interrupted.

  Further, at the end of application, as the needle 6 rises, the central portion of the liquid reservoir 14 at the tip of the nozzle can be selectively pulled back to the nozzle side, and the residual charge held by the liquid reservoir 14 immediately after the voltage application is stopped. It is possible to significantly reduce the time that is not separated from the coating object 4 due to the influence of the above and is held unstable. As a result, the timing control for stopping the relative movement between the nozzle 2 and the application target 4 for ending application is facilitated, and the position at which the liquid reservoir 14 is separated from the application target 4 becomes as intended. . As a result, even at the end of coating, precise coating can be realized without causing the line width to increase or break. Further, since the time required for coating at the end can be shortened, the production tact can be shortened.

− Condition 2 −
In Condition 1, θ1 = 20 °, θ2 = 15 °, and θ3 = 15 °. However, in Condition 2, the rest is the same as Condition 1 except that θ3 = 10 °. Moreover, the evaluation result of the state of the application | coating start / end using the parameter | index similar to the conditions 1 is shown in FIG.

  In condition 2, θ1> θ2> θ3 and the contact angle of the needle tip surface 19 is the lowest, so that the speed of expansion / contraction of the liquid reservoir 14 on the needle tip surface 19 is higher than in the case of condition 1. In addition, stable continuous application can be realized without the liquid reservoir 14 being interrupted.

  Further, since the needle tip surface 19 has the lowest contact angle, it is possible to improve the responsiveness at the time of separating the liquid reservoir 14 from the needle tip surface 19 at the end of application compared to the condition 1. As a result, the timing control for stopping the relative movement between the nozzle 2 and the application target 4 for ending application is facilitated, and the position at which the liquid reservoir 14 is separated from the application target 4 becomes as intended. . As a result, even at the end of coating, precise coating can be realized without causing the line width to increase or break. Further, since the time required for coating at the end can be shortened, the production tact can be shortened.

− Condition 3 −
In condition 2, the contact angle of the needle side surface 20 with respect to the nano Ag ink 16 was the same 15 ° in both the portion located inside the nozzle 2 and the portion protruding outside the nozzle 2 as shown in FIG. However, under this condition 3, as shown in FIGS. 7 and 8, two regions 22 and 23 having different contact angles on the side surfaces of the needles 6 that are located closer to the application object 4 than the nozzle tip surface 18 at the time of application. have. The contact angle θ4 of the region 22 on the nozzle side was 15 °, and the contact angle θ5 of the region 23 on the tip side of the needle 6 was 13 °. The other conditions were the same as those in condition 2. FIG. 6 shows the evaluation results of the coating start / end state using the same index as in Condition 1.

  Under this condition 3, since the needle tip surface 19 has the lowest contact angle, the effect that the liquid reservoir 14 can be held on the needle tip surface 19 can be improved as compared with the condition 1. In addition, the contact angle θ4 of the nozzle-side region 22 is greater than or equal to the contact angle θ5 of the region 23 on the tip side of the needle 6 in the side surface portion of the needle 6 that protrudes closer to the application object 4 than the nozzle tip surface 18 during application. As a result, the effect of holding the nano Ag ink 16 at the nozzle tip can be improved as compared with the case of Condition 2. As a result, the expansion and contraction of the liquid reservoir 14 can be speeded up, and stable continuous application can be realized without the liquid reservoir 14 being interrupted.

  Further, since the needle tip surface 19 has the lowest contact angle, the effect of holding the liquid reservoir 14 on the needle tip surface 19 is improved as compared with the condition 1. Therefore, the responsiveness when separating the liquid reservoir 14 at the end of application is improved. improves.

  In addition, the contact angle θ4 of the nozzle-side region 22 is changed to the contact angle θ5 of the tip-side region 23 in the nozzle-side region 22 of the side surface of the needle that protrudes closer to the application target 4 than the nozzle tip surface 18 during application. By setting it as the above, the effect which hold | maintains the nano Ag ink 16 on the needle front end surface 19 can be improved compared with the case of the condition 2. As a result, the timing control for stopping the relative movement between the nozzle 2 and the application target 4 for ending application is facilitated, and the position at which the liquid reservoir 14 is separated from the application target 4 becomes as intended. . As a result, even at the end of coating, precise coating can be realized without causing the line width to increase or break. Further, since the time required for coating at the end can be shortened, the production tact can be shortened.

  Under this condition 3, θ2 = θ4, but by setting θ2> θ4, stable liquid supply from the inside of the nozzle to the liquid reservoir 14 formed at the tip of the nozzle is possible compared to the case of θ2 = θ4. It becomes. As a result, stable continuous application can be realized without the liquid reservoir 14 being interrupted.

− Condition 4 −
In condition 3, the needle 6 was θ4 = 15 °, θ5 = 13 °, θ3 = 10 °, and θ5> θ3. In this condition 4, θ5 = θ3 was set. Other conditions were the same as Condition 3.

  Here, when the liquid is applied, the contact angle θ4 of the nozzle side region 22 of the side surface of the needle that protrudes closer to the application target 4 than the nozzle tip surface 18 is 15 °, and the contact angle θ5 of the region 23 on the tip side of the needle 6. Is 10 °, which is smaller than the contact angle θ4. Moreover, the evaluation result of the state of the application | coating start / end using the parameter | index similar to the conditions 1 is shown in FIG.

  In the electrostatic application of condition 4, since the needle tip surface 19 has the lowest contact angle, the effect that the liquid reservoir 14 can be held on the needle tip surface 19 can be improved as compared with condition 1. In addition, by making the contact angle θ5 of the tip side region 23 of the side surface of the needle that protrudes closer to the application target 4 than the nozzle tip surface 18 during application equal to the contact angle θ3 of the needle tip surface, In comparison, the effect of holding the nano Ag ink 16 at the nozzle tip can be improved. As a result, the expansion and contraction of the liquid reservoir 14 can be speeded up, and stable continuous application can be realized without the liquid reservoir 14 being interrupted.

  In addition, since the needle tip surface 19 has the lowest contact angle at the application end, the effect of holding the liquid reservoir 14 on the needle tip surface 19 can be improved as compared with Condition 1, and thus the responsiveness when separating the liquid reservoir 14 is improved. Can be connected. In addition, by making the contact angle θ5 of the region 23 on the tip side of the needle side surface portion that protrudes closer to the application object 4 than the nozzle tip surface 15 at the time of application equal to the contact angle θ3 of the needle tip surface, In comparison, the effect of holding the nano Ag ink 16 at the nozzle tip can be improved. As a result, the timing control for stopping the relative movement between the nozzle 2 and the application target 4 for ending application is facilitated, and the position at which the liquid reservoir 14 is separated from the application target 4 becomes as intended. . As a result, even at the end of coating, precise coating can be realized without causing the line width to increase or break. Further, since the time required for coating at the end can be shortened, the production tact can be shortened.

− Condition 5 −
The needle 6 under each of the above conditions used a round bar with a constant diameter up to the tip, but under this condition 5, the tip of the needle 6 is formed in a tapered shape as shown in FIG. It is different from the case of each condition.

  A needle taper portion 24 having a needle diameter of 50 μm to 25 μm is formed in the range of 20 mm from the needle tip at the tip of the needle 6 under the condition 5. FIG. 6 shows the evaluation results of the coating start / end state using the same index as in Condition 1.

  In this condition 5, since the needle taper portion 24 is provided, it is possible to suppress an increase in the flow resistance of the nano Ag ink 16 at the nozzle tip as compared with the condition 1, and from the inside of the nozzle to the nozzle tip at the time of application. A stable liquid supply to the liquid reservoir 14 to be formed becomes possible. As a result, the expansion and contraction of the liquid reservoir 14 can be speeded up, and stable continuous application can be realized without the liquid reservoir 14 being interrupted.

  Further, since the needle taper portion 24 is provided, it is possible to suppress an increase in the flow resistance of the nano Ag ink 16 at the nozzle tip as compared with the condition 1 at the application end, and from the tip of the nozzle 2 at the time of non-application. In addition, by operating the needle driving unit 10 by the control unit 13 so that the start position P1 of the needle taper portion 24 is located on the inner side, it is possible to improve the responsiveness when the liquid reservoir 14 is separated. As a result, the timing control for stopping the relative movement between the nozzle 2 and the application target 4 for ending application is facilitated, and the position at which the liquid reservoir 14 is separated from the application target 4 becomes as intended. . As a result, even at the end of coating, precise coating can be realized without causing the line width to increase or break. Further, since the time required for coating at the end can be shortened, the production tact can be shortened.

− Condition 6 −
Under condition 5, the contact angle of nano Ag ink on the side surface of the needle 6 was θ2 = 15 °, and the contact angle of nano Ag ink on the needle tip surface 19 was θ3 = 15 °. The contact angle θ3 of the surface 19 was 10 °. Other conditions were the same as Condition 5. Moreover, the evaluation result of the state of the application | coating start / end using the parameter | index similar to the conditions 1 is shown in FIG.

  Under this condition 6, since the needle tip surface 19 has the lowest contact angle, the effect of holding the liquid reservoir 14 on the needle tip surface 19 can be improved as compared with the case of condition 5. As a result, the expansion and contraction of the liquid reservoir 14 can be speeded up, and stable continuous application can be realized without the liquid reservoir 14 being interrupted.

  Further, since the needle tip surface 19 has the lowest contact angle, the effect of holding the liquid reservoir 14 on the needle tip surface 19 can be improved at the end of application as compared with the case of Condition 5, so that the liquid reservoir 14 can be separated. This can lead to improved responsiveness. As a result, the timing control for stopping the relative movement between the nozzle 2 and the application target 4 for ending application is facilitated, and the position at which the liquid reservoir 14 is separated from the application target 4 becomes as intended. . As a result, even at the end of coating, precise coating can be realized without causing the line width to increase or break. Further, since the time required for coating at the end can be shortened, the production tact can be shortened.

− Condition 7 −
In condition 5 and condition 6, the contact angle of the nano Ag ink of the needle taper portion 24 was single, but in condition 7, as shown in FIG. The only difference is that the regions 25 and 26 having different contact angles of the nano Ag ink are formed on the side surface of the needle 6 protruding to the 4 side. Other conditions were the same as condition 6.

  Here, as shown in FIG. 11, the contact angle of the nozzle-side region 25 is θ6 = 15 °, and the contact angle of the needle-tip region 26 is θ7 = 13 °. FIG. 6 shows the evaluation results of the coating start / end state using the same index as in Condition 1.

  Under this condition 7, the needle tip surface 19 has the lowest contact angle, so that the effect of holding the liquid reservoir 14 at the needle tip can be improved as compared with the condition 5. In addition, the contact angle θ6 of the nozzle-side region 25 is set to be equal to or larger than the contact angle θ7 of the tip-side region 26 in the needle taper portion 24 protruding from the nozzle tip surface 18 to the application target 4 side during application. Compared to the condition 6, the effect of holding the nano Ag ink 16 on the needle tip surface 19 can be improved. As a result, the expansion and contraction of the liquid reservoir 14 can be speeded up, and stable continuous application can be realized without the liquid reservoir 14 being interrupted.

  In addition, since the needle tip surface 19 has the lowest contact angle, the effect of holding the liquid reservoir 14 on the needle tip surface 19 can be improved at the end of application compared to the condition 5, so that the liquid reservoir 14 can be separated. Can improve the responsiveness. In addition, the contact angle θ6 of the nozzle-side region 25 is set to be equal to or larger than the contact angle θ7 of the tip-side region 26 in the needle taper portion 24 protruding from the nozzle tip surface 15 to the application target 4 side during application. Compared to the condition 6, the effect of holding the nano Ag ink 16 on the needle tip surface 19 can be improved. As a result, the timing control for stopping the relative movement between the nozzle 2 and the application target 4 for ending application is facilitated, and the position at which the liquid reservoir 14 is separated from the application target 4 becomes as intended. . As a result, even at the end of coating, precise coating can be realized without causing the line width to increase or break. Further, since the time required for coating at the end can be shortened, the production tact can be shortened.

− Condition 8 −
In Condition 7, θ6 = 15 ° and θ7 = 13 °. However, in Condition 8, θ6 = 15 ° and θ7 = 10 °. Other conditions were the same as condition 7. Moreover, the evaluation result of the state of the application | coating start / end using the parameter | index similar to the conditions 1 is shown in FIG.

  Under this condition 8, the needle tip surface 19 has the lowest contact angle, so that the effect of holding the liquid reservoir 14 at the needle tip can be improved as compared with the condition 5. In addition, by making the contact angle θ7 of the region 26 on the tip side of the needle taper portion that protrudes closer to the application target 4 than the nozzle tip surface 18 at the time of application equal to the contact angle θ3 of the needle tip surface 19, Condition 7 As compared with the case of, the effect of holding the nano Ag ink 16 at the nozzle tip can be improved. As a result, the expansion and contraction of the liquid reservoir 14 can be speeded up, and stable continuous application can be realized without the liquid reservoir 14 being interrupted.

  Further, since the needle tip surface 19 has the lowest contact angle, the effect of holding the liquid reservoir 14 at the tip of the needle can be improved at the end of application compared to the case of Condition 5. In addition, by making the contact angle θ7 of the region 26 on the distal end side of the needle taper portion 24 protruding to the application object 4 side from the nozzle distal end surface 18 during application equal to the contact angle θ3 of the needle distal end surface 19, Compared to the case of No. 7, the effect of holding the nano Ag ink 16 at the nozzle tip can be improved. As a result, the timing control for stopping the relative movement between the nozzle 2 and the application target 4 for ending application is facilitated, and the position at which the liquid reservoir 14 is separated from the application target 4 becomes as intended. . As a result, even at the end of coating, precise coating can be realized without causing the line width to increase or break. Further, since the time required for coating at the end can be shortened, the production tact can be shortened.

  The present invention makes it possible to accurately form a pattern with high linearity at high speed and continuously. For example, organic EL, plasma display, liquid crystal display, touch panel, circuit board, semiconductor, solar cell, lithium secondary The present invention can be applied to a printing manufacturing process for producing a device such as a battery.

DESCRIPTION OF SYMBOLS 1 Liquid 2 Nozzle 3 Nozzle tip 4 Application object 5 Power supply part 6 Needle 7 Liquid supply part 8 Electrode plate 9 Nozzle drive part 10 Needle drive part 11 Stage 12 Stage drive part 13 Control part 14 Liquid reservoir 15 at the nozzle tip Nozzle inner diameter of 16 Nano Ag ink 17 Needle diameter at nozzle tip 18 Nozzle tip surface 19 Needle tip surface 20 Needle side surface 21 Clearance 22 between nozzle inner wall and needle side surface at nozzle tip surface Side surface of needle protruding beyond nozzle tip surface Region 23 of the contact angle θ4 in the region 24 of the contact angle θ5 on the side surface of the needle protruding from the nozzle tip surface 24 Needle taper portion 25 Region of the contact angle θ6 on the nozzle side in the side surface portion of the needle taper portion Side surface of the needle taper portion Of the contact angle θ7 on the front end side

Claims (9)

A nozzle tip of a nozzle in which a liquid is stored is arranged to face an application object, a potential difference is applied between the liquid and the application object at the time of application, and the nozzle tip is directed to the application object side. The liquid reservoir is formed to extend, and at the time of application, the tip of the needle disposed in the nozzle is moved from the retracted position to the advanced position so that the tip of the needle protrudes into the liquid reservoir. The tip of the reservoir is brought into contact with the object to be coated, the tip of the liquid reservoir is brought into contact with the object to be coated, and then the tip of the needle is protruded from the nozzle and the object to be coated and the nozzle are moved. relatively moved in the horizontal direction, the electrostatic coating how to continuously apply the liquid to the object to be coated. 2. The electrostatic coating method according to claim 1, wherein at the end of coating, the potential difference is made smaller than that at the time of coating and the tip of the needle is moved back into the nozzle from the tip of the nozzle. An electrostatic coating apparatus that draws the liquid from the nozzle by applying a potential difference between the liquid in the nozzle and the coating object, and coats the coating object.
A power supply unit for applying a predetermined voltage between the liquid and the application target;
A needle that can move up and down in the nozzle;
A needle drive section for driving the needle up and down;
At the time of application, the power supply unit is controlled so as to form a liquid pool of the liquid extending toward the application target at the tip of the nozzle, and the tip of the needle is moved from the retracted position to the advanced position. The needle drive unit is operated so that the tip of the needle protrudes into the liquid reservoir, the tip of the liquid reservoir is brought into contact with the application object, and then the tip of the needle is protruded from the nozzle. the nozzle and the object to be coated is relatively moved in a horizontal direction in a state, an electrostatic coating apparatus having said you continuously applying the liquid to the object to be coated control unit. The electrostatic coating apparatus according to claim 3, wherein the control unit is configured to raise the needle until the tip is located inside the nozzle when the liquid is not applied. The electrostatic coating apparatus according to claim 3, wherein the needle has a tapered portion that gradually becomes thinner toward a tip. 6. The controller according to claim 5, wherein the control unit is configured to operate the needle driving unit so that a start position of the tapered portion of the needle is located on an inner side of a tip of the nozzle when the liquid is not applied. The electrostatic coating apparatus as described. When the contact angle of the liquid at the end surface of the tip of the nozzle is θ1, the contact angle of the liquid at the side of the needle is θ2, and the contact angle of the liquid at the tip of the needle is θ3, θ1> θ2 and θ1> The electrostatic coating apparatus according to claim 5 or 6, wherein θ3. In the portion of the liquid that is applied to the application object side from the tip of the nozzle when the liquid is applied, the side of the needle is closer to the tip of the needle than the region where the contact angle of the liquid is θ2. The electrostatic coating apparatus according to claim 7, wherein the electrostatic coating apparatus has a region where the contact angle of the liquid is θ4, and θ2 ≧ θ4. 9. The gap between the inner wall of the nozzle and the outer wall of the needle is larger than the diameter of the needle at the tip of the nozzle when the liquid is applied. Electrostatic coating device.

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