Liquid material coating unit, coating apparatus, and coating method

Abstract

A liquid material coating unit (4) includes a coating needle (24) and a coating liquid container (21). The coating liquid container (21) includes a joint section (25) and a needle movement section (26). The joint section (25) extends in a horizontal direction. The needle movement section (26) extends from the joint section (25) in a vertical direction. An amount (P) of protrusion of the coating needle (24) allowed to protrude from a through-hole (22) of the coating liquid container (21) in the vertical direction is greater than or equal to 1 mm and less than or equal to 3 mm. A first width (W1) of the needle movement section (26) in the horizontal direction is less than or equal to 5 mm. A length of the needle movement section (26) extending from the joint section (25) to the through-hole (22) in the vertical direction is greater than or equal to 5 mm.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a liquid material coating unit, a liquid material coating apparatus, and a liquid material coating method. BACKGROUND

[0002] During packaging of electronic components, a liquid material such as a conductive material or an adhesive is coated. The recent trend toward miniaturization of electronic components requires stable coating of a small amount of such a liquid material.

[0003] Further, in order to fix a component such as a minute optical component using an adhesive, an adhesive composed of a mixture of two liquids and cured by a chemical reaction is widely used. This is because a single-component moisture-curable adhesive requires time to cure.

[0004] A process of coating a liquid material to an electronic component and a process of coating an adhesive composed of a mixture of two liquids are preferably performed using a coating needle disclosed in, for example, Japanese Patent Laid-Open No. 2007-268353. In this case, a liquid material in a coating liquid container is attached to a coating needle in the coating liquid container. Subsequently, the coating needle protrudes from a through-hole of the coating liquid container, and the liquid material attached to the coating needle is transferred to a coating object. The use of the coating needle allows a fine pattern to be coated to a liquid material in a wide viscosity range.

[0005] REFERENCE LIST

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Laid-Open No. 2007-268353 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] For coating a liquid material using a coating needle, it is important to control a so-called protrusion amount, which is a distance by which the coating needle protrudes from a coating liquid container. That is, when the protrusion amount is too large, air bubbles can be mixed into the liquid material in the coating liquid container, or a coating diameter of a coating pattern can be changed. Further, when the protrusion amount is too small, the coating diameter of the coating pattern can be increased.

[0010] The present disclosure has been made in view of the problems as described above. Therefore, an object of the present disclosure is to provide a liquid material coating unit, a liquid material coating apparatus, and a liquid material coating method capable of preventing air bubbles from being mixed into a liquid material and capable of stably supplying a liquid material having a fine coating diameter.

[0011] TECHNICAL MEANS FOR SOLVING THE PROBLEMS

[0012] A liquid material coating unit according to the present disclosure includes a coating needle and a coating liquid container. The coating needle coats a liquid material. The coating liquid container holds the liquid material therein and is formed with a through-hole at a bottom that allows the coating needle to pass through. The coating liquid container includes a joint section and a needle movement section. The joint section extends in a horizontal direction that intersects with an extending direction of the coating needle. The needle movement section extends from the joint section to the through-hole in a vertical direction that coincides with the extending direction of the coating needle. An amount of protrusion that allows the coating needle to protrude from the through-hole of the coating liquid container in the vertical direction is greater than or equal to 1 mm and less than or equal to 3 mm. A first width of the needle movement section in the horizontal direction is less than or equal to 5 mm. A length of the needle movement section that extends from the joint section to the through-hole in the vertical direction is greater than or equal to 5 mm.

[0013] In a liquid material coating method according to the present disclosure, a coating liquid container formed with a through-hole at a bottom is aligned on a coating target of a liquid material, in which the liquid material is held in the coating liquid container, and a distal end of a coating needle is immersed in the liquid material. The coating liquid container is brought close to the coating target. The coating needle is moved in an extending direction of the coating needle to coat the liquid material to the coating target. In the above-mentioned coating process, an amount of protrusion that allows the coating needle to protrude from the through-hole of the coating liquid container in the extending direction is greater than or equal to 1 mm and less than or equal to 3 mm. In the above-mentioned approaching process, the coating liquid container is placed so as to be at least partially surrounded by the coating target.

[0014] Inventive Effects

[0015] According to the present disclosure, it is possible to provide a liquid material coating unit, a liquid material coating apparatus, and a liquid material coating method that can prevent air bubbles from being mixed into a liquid material and that can stably supply a liquid material having a minute coating diameter. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic perspective view that shows a liquid material coating apparatus according to the present embodiment.

[0017] Figure 2 is a view that schematically shows a configuration of a portion of a liquid material coating unit according to the present embodiment.

[0018] Figure 3 is a schematic front view of a liquid material coating unit according to the present embodiment, showing a first example of a configuration of the liquid material coating unit.

[0019] Figure 4 is a schematic side view of a liquid material coating unit according to the present embodiment, showing a first example of a configuration of the liquid material coating unit.

[0020] Figure 5These are schematic front and side views of a liquid material coating unit according to this embodiment, showing a second example of the construction of the liquid material coating unit.

[0021] Figure 6 These are schematic front and side views of a liquid material coating unit according to this embodiment, illustrating a third example of the construction of a liquid material coating unit.

[0022] Figure 7 It is used for Figure 6 A schematic diagram illustrating the cam component of the coating mechanism is shown.

[0023] Figure 8 This is a schematic diagram for describing a liquid material coating method using a liquid material coating unit according to this embodiment.

[0024] Figure 9 This is a schematic diagram used to describe a liquid material coating method using a liquid material coating unit according to a comparative example.

[0025] Figure 10 This is a schematic diagram illustrating a coating process using a coating needle with a normal amount of protrusion.

[0026] Figure 11 This is for the purpose of... Figure 10 A schematic diagram illustrating a coating process using a coating needle with an extremely small amount of protrusion is provided for comparison.

[0027] Figure 12 This is a graph showing the experimental results of coating diameter variation when the protrusion amount is set to 3 mm.

[0028] Figure 13 This is a graph showing the experimental results of coating diameter variation when the protrusion amount is set to 15 mm.

[0029] Figure 14 This is a schematic diagram showing the initial vertical position of the coating needle in the coating liquid container.

[0030] Figure 15 This is a schematic diagram used to describe the location of the gap.

[0031] Figure 16 It is along Figure 15 A schematic cross-sectional view of the XVI-XVI section.

[0032] Figure 17 This is a schematic diagram illustrating how air bubbles are incorporated according to the coating interval.

[0033] Figure 18 This is a flowchart of a liquid material coating method based on the third working example. DETAILED DESCRIPTION

[0034] Hereinafter, the present embodiment will be described with reference to the drawings.

[0035] Figure 1 is a schematic perspective view showing a liquid material coating apparatus according to the present embodiment. Referring to Figure 1 The liquid material coating apparatus 200 according to the present embodiment includes a base 12 provided on a floor surface, an X-axis stage 1, a Y-axis stage 2, a Z-axis stage 3, a liquid material coating unit 4, an observation optical system 6, a CCD camera 7 connected to the observation optical system 6, and a controller 11.

[0036] The Y-axis stage 2 movable in the Y-axis direction in Figure 1 The Y-axis stage 2 movable in the Y-axis direction in Figure 1 A thin plate substrate is shown as the coating object 5. However, this is merely an example, and the coating object 5 can be, for example, a bottom of a groove described below.

[0037] On the base 12, a portal structure is provided installed with a guide rail across the Y-axis stage 2 in the X-axis direction. The X-axis stage 1 movable in the X-axis direction is placed on the structure. For example, a ball screw moves the X-axis stage 1 in the X-axis direction.

[0038] The Z-axis stage 3 is placed on a movable body of the X-axis stage 1, and the liquid material coating unit 4 and the observation optical system 6 are placed on the Z-axis stage 3. The liquid material coating unit 4 and the observation optical system 6 are capable of moving in the X-axis direction with the Z-axis stage 3. The liquid material coating unit 4 is provided to coat a coating liquid to a coating surface (upper surface) of the coating object 5 using a coating needle provided in the liquid material coating unit 4. The observation optical system 6 is provided to observe a coating position of the coating object 5. The CCD camera 7 of the observation optical system 6 converts an observed image into an electric signal. The Z-axis stage 3 supports the liquid material coating unit 4 and the observation optical system 6 in the Z-axis direction.

[0039] The controller 11 includes a control panel 8, a monitor 9, and a control computer 10, and controls the X-axis stage 1, the Y-axis stage 2, the Z-axis stage 3, the liquid material coating unit 4, and the observation optical system 6. The control panel 8 is used to input instructions to the control computer 10. The monitor 9 displays image data obtained by conversion by the CCD camera 7 of the observation optical system 6, and data output from the control computer 10.

[0040] When drawing a circuit pattern on the coating object 5, the drawing position of the coating object 5 located directly below the observation optical system 6 is moved by using the X-axis stage 1 and the Y-axis stage 2, and the drawing start position is observed and confirmed by using the observation optical system 6. Next, a circuit pattern is drawn from the drawing start position thus determined. The coating object 5 is moved step by step from the drawing start position by the X-axis stage 1 and the Y-axis stage 2, so that the drawing position is brought immediately below the liquid material coating unit 4. When the movement is completed, the liquid material coating unit 4 is driven to perform coating. The above procedure is continuously repeated to draw a circuit pattern.

[0041] The relationship between the position of the lowered end of the coating needle 24 and the focal point position of the observation optical system 6 is stored in advance, and during drawing, the position of the focal point of the observation optical system 6 on the image is used as a reference in the Z-axis direction, and after the coating needle 24 is moved to a height at which the coating needle 24 comes into contact with the coating object 5 in the Z-axis direction by the Z-axis stage, coating is performed. When the area of the circuit pattern to be drawn is large, and the height of the coating position of the coating object 5 greatly changes during drawing, the focal point position is checked as necessary during drawing, and coating is performed after the position in the Z-axis direction is corrected. At this time, the focal point position can be adjusted by an autofocus method using image processing, or by a method of constantly detecting the height position of the surface to be coated of the coating object 5 by using a laser sensor or the like, and performing correction in real time.

[0042] Then, the liquid material coating unit 4 according to the present embodiment will be described in detail with reference to Figures 2 to 7

[0043] Figure 2 is a view schematically showing the configuration of a part of the liquid material coating unit according to the present embodiment. With reference to Figure 2 The liquid material coating unit 4 according to the present embodiment includes a coating liquid container 21 and a coating needle 24. The coating liquid container 21 holds a liquid material 100 therein. The coating liquid container 21 has a through-hole 22 formed at a bottom portion that is the lowermost portion in Figure 2 The coating needle 24 is provided in the coating liquid container 21 in a manner so as to be able to pass through the coating liquid container 21.

[0044] ​The coating needle 24 applies the liquid material 100 held in the coating liquid container 21. Figure 2 In the process, the distal end 23, which is the lowest part of the coating needle 24, is immersed in the liquid material 100. As the coating needle 24 moves downward, at least the distal end 23 passes through the through hole 22 to protrude from the through hole 22. This allows the coating needle 24 to apply the liquid material 100 to the object to be coated.

[0045] The coating liquid container 21 includes a connecting section 25 and a needle motion section 26. As described later, the liquid material coating unit 4 includes a drive unit such as a linear motion mechanism or a servo motor. The connecting section 25 is the section where the main components of the liquid material coating unit 4, such as the linear motion mechanism, are connected to the coating liquid container 21. Figure 2 As shown, in a state where the coating needle 24 is allowed to pass through the through-hole 22 into the coating liquid container 21, the connecting section 25 extends along the same direction as the extension of the coating needle 24 passing through the coating liquid container 21. Figure 2 The horizontal direction intersecting the vertical direction in the middle ( Figure 2 The needle movement section 26 extends in a direction perpendicular to the extension direction of the coating needle 24. Figure 1 The section extending from the connecting section 25 to the through hole 22 (in the Z direction). In other words, in Figure 2 In this section, the needle movement segment 26 is located below the connecting segment 25 and extends vertically below the connecting segment 25. The coating needle 24 moves vertically within the needle movement segment 26.

[0046] Allow coating needles 24 along Figure 2 The vertical protrusion P from the through-hole 22 of the coating liquid container 21 is greater than or equal to 1 mm and less than or equal to 3 mm. That is, when Figure 2 When the coating needle 24 shown descends to apply liquid material 100 to the coating object 5, the protrusion amount P, that is, the distance by which the distal end 23 protrudes downward from the through hole 22, is greater than or equal to 1 mm and less than or equal to 3 mm. The state of the distal end 23 protruding downward from the through hole 22 is determined by... Figure 2 The dotted line indicates this. Note that the protrusion P can be greater than or equal to 1.5 mm and less than or equal to 3 mm, and more preferably greater than or equal to 2 mm and less than or equal to 3 mm. More preferably, the protrusion P is greater than or equal to 2.5 mm and less than or equal to 3 mm. As an example, the protrusion P is 3 mm.

[0047] Needle movement section 26 along Figure 2 The first width W1 in the left-right direction is less than or equal to 5mm. That is, for example, when from... Figure 2 When observing the needle movement section 26 from above, the maximum width of the outer periphery in the horizontal direction is less than or equal to 5 mm. For example, W1 is 5 mm.Figure 2 When the lowest part of the needle movement section 26 has a tapered shape, the first width W1 represents the maximum width of the outer periphery of the region other than the region with the tapered shape in the horizontal direction. In the region, the maximum width of the outer periphery is substantially uniform in the vertical direction.

[0048] Needle movement section 26 along Figure 2 The vertical length T extending from the connecting section 25 to the through hole 22 is greater than or equal to 5 mm. That is, the needle movement section 26 extends downward from the lowest part of the connecting section 25 by at least 5 mm. As an example, T is 15 mm.

[0049] In the liquid material coating unit 4 with the above-mentioned characteristics, along Figure 2 The first width W1 in the left-right direction is less than or equal to five times the second width W2, and the second width W2 is along... Figure 2 The cross-section of the coating needle 24 extending vertically in the middle. Here, except for the inclined shape due to tapering process, etc. Figure 2 Outside of the distal end 23 and similar areas, along the edge of the coating needle 24 Figure 2 The portion extending vertically corresponds to a region in which the maximum width of the outer periphery is substantially uniform along the vertical direction. That is, in the region of the coating needle 24 with a second width W2, the outer periphery of the coating needle 24 extends straight along the vertical direction and has a uniform outer periphery width. For example, the second width W2 refers to the portion extending vertically from the outer periphery of the coating needle 24 with a uniform outer periphery width. Figure 3 The maximum width of the outer perimeter in the horizontal direction is observed from above when the coating needle 24 is viewed. As an example, W1 is 5 mm and W2 is 1 mm.

[0050] like Figure 4 As shown, the coating object 5 preferably has, for example, a groove shape, a recessed shape, or a container shape, which have a side surface portion that can surround the coating needle 24 when the coating needle 24 moves downward, and a bottom surface portion located below the side surface portion and coated with the liquid material 100. The lateral distance D across the processed side surface portion surrounding the coating needle 24 of the coating object 5 is, for example, greater than or equal to 6.5 mm, and can be 12 mm or 17 mm.

[0051] Liquid material 100 can be a conductive material used, for example, to mount a crystal oscillator. Alternatively, liquid material 100 can be a so-called catalytic material coated onto a microelectromechanical system (MEMS) gas sensor. Alternatively, liquid material 100 can be an adhesive coated onto a light-emitting diode (LED). Liquid material 100 can be a mixture of two liquids.

[0052] The liquid material 100 can be a liquid having fine particles suspended therein. For example, in the case where the liquid material 100 is an adhesive, reinforcing particles for the adhesive can be included as the fine particles. The liquid material 100 is not limited to a pure liquid free from particles, and can also be a liquid including particles. Specifically, the liquid material 100 can be a conductive paste including industrial metal particles. In this case, the fine particles are the metal particles. The liquid material 100 can be an adhesive including inorganic particles. In this case, the fine particles are the inorganic particles.

[0053] Note that a good balance between the surface tension across the edge of the through-hole 22 and the pressure applied by the weight of the liquid material 100 in the coating liquid container 21 prevents the liquid material 100 in the coating liquid container 21 from leaking out of the through-hole 22.

[0054] Figure 3 is a schematic front view of a liquid material coating unit according to the present embodiment, showing a first example of the configuration of the liquid material coating unit. Figure 2 is a schematic side view of a liquid material coating unit according to the present embodiment, showing a first example of the configuration of the liquid material coating unit. Reference is made to Figure 2 and 4 The liquid material coating unit 4 includes, in addition to the coating liquid container 21 shown in Figure 5 , a servo motor 120, a motor driver 121, a coating needle holder 102, a coating needle holder housing 104, a coating needle holder fixed section 106, and a linear motion mechanism 130.

[0055] The servo motor 120 is provided as a drive source for moving the coating needle 24 up and down. The coating needle holder 102 holds one coating needle 24 having a tapered tip. The linear motion mechanism 130 moves the coating needle holder 102 up and down in response to the rotation of the servo motor 120. The motor driver 121 controls the rotation of the servo motor 120, thereby moving the coating needle holder 102 up and down at an appropriate speed.

[0056] The linear motion mechanism 130 includes a home sensor 118, an eccentric plate 116, an eccentric shaft 114, a linear guide 132, a coupling plate 112, a movable section 108, a coupling shaft 110, bearings 122, 124.

[0057] The eccentric plate 116 is rotated by the servo motor 120 and is attached to a rotation shaft of the servo motor 120 extending orthogonally to the vertical movement direction of the coating needle holder 102. The eccentric plate 116 is provided with the eccentric shaft 114 at a position eccentric to the rotation shaft of the servo motor 120.

[0058] Origin sensor 118 detects the origin defined on eccentric plate 116 and outputs the origin to motor driver 121. The origin is closest to origin sensor 118 when eccentric plate 116 is aligned with a reference rotation angle.

[0059] In the movable section 108, a coating needle holder 102 is attached to a coating needle holder fixed section 106, and a coating needle 24 is held with its distal end 23 facing downward from the lower surface of the coating needle holder 102. A linear guide fabric 132 supports the movable section 108 to which the coating needle holder 102 is fixed, and the movable section 108 is movable in a vertical direction.

[0060] The connecting plate 112 connects the connecting shaft 110, which is located in the movable section 108 that moves up and down, to the coating needle holder 102 and the eccentric shaft 114 with a fixed length.

[0061] Bearing 122 supports a connecting plate 112 that can rotate about an eccentric shaft 114. Bearing 124 supports a connecting plate 112 that can rotate about a connecting shaft 110.

[0062] The movable section 108 is attracted toward the retaining pin 128 by a spring 126 to prevent vibrations caused by loosening of bearings 122, 124 during operation. Applying a preload to bearings 122, 124 to eliminate loosening allows for a configuration without spring 126.

[0063] When the servo motor 120 is driven to rotate the eccentric plate 116, the coating needle 24 reciprocates in the vertical direction in response to the vertical movement of the eccentric shaft 114. When the eccentric plate 116 rotates in one direction, the connecting shaft 110 moves up and down with a vertical stroke ΔZ. That is, the coating needle 24... Figure 5 The needle moves vertically in the motion section 26 shown. This causes the distal end 23 of the coating needle 24 to repeatedly coat the liquid material 100 and then retract into the liquid material 100 after coating.

[0064] Figure 5 These are schematic front and side views of the liquid material coating unit according to this embodiment, showing a second example of the construction of the liquid material coating unit. That is, Figure 5 (A) is a schematic front view. Figure 3 (B) is a schematic side view. (See reference...) Figure 4 The second example is constructed similarly to... Figure 5 and Figure 3 The first example shown is essentially the same, therefore, a detailed description will not be given below. Note that, as Figure 4 As shown in the second example, the extending direction of the connecting section 25 of the coating liquid container 21 can be substantially aligned with the left-right direction of the servo motor 120. Alternatively, asFigures 3 to 5 and Figures 3 to 5 As shown in the first example, the extending direction of the connecting section 25 of the coating liquid container 21 intersects (e.g., substantially orthogonal to) the left-right direction of the extending direction of the servo motor 120. Furthermore, Figure 6 The liquid material coating unit 4 shown converts the rotation of the servo motor 120 into linear motion to move the coating needle 24 up and down. However, this configuration is not limited to such an example. For example, as a mechanism for making the coating needle 24 reciprocate linearly, such as Figure 6 As shown, any one of the following groups can be used: an electric linear motion actuator using a screw, a pneumatic cylinder, and a solenoid.

[0065] Figure 6 These are schematic front and side views of the liquid material coating unit according to this embodiment, illustrating a third example of the construction of the liquid material coating unit. That is, Figure 7 (A) is a schematic front view. Figure 6 (B) is a schematic side view. Figure 6 It is used for Figure 7 A schematic diagram illustrating the cam component of the coating mechanism is shown. (Refer to...) Figure 2 and Figure 1 In addition to the liquid material coating unit 4 of the third embodiment Figure 7 Besides the coating liquid container 21 shown, the main components include a servo motor 120, a cam 143, a bearing 122, a cam connecting plate 145, a movable section 108, and a coating needle holder 102. The coating needle holder 102 holds the coating needle 24. The servo motor 120 is mounted so that its rotation axis... Figure 7 The Z-axis direction is shown. Cam 143 is connected to the rotation axis of servo motor 120. Cam 143 can rotate about the rotation axis of servo motor 120.

[0066] The cam 143 includes a central section connected to the rotating shaft of the servo motor 120 and a flange section connected to one end of the central section. For example... Figure 7 As shown in (A), the upper surface of the flange section (the surface adjacent to the servo motor 120) is a cam surface 161. The cam surface 161 is formed in an annular shape along the outer periphery of the central section and is inclined, thereby changing the distance from the bottom surface of the flange section. Specifically, as... Figure 6 As shown in (B), the cam surface 161 includes an upper flat region 162 having a maximum distance from the bottom surface of the flange section, a lower flat region 163 having a minimum distance from the upper flat region 162 and spaced apart from the bottom surface of the flange section, and an inclined section connecting the upper flat region 162 and the lower flat region 163. Here, Figure 6(B) is an expanded view of the flange section including the cam surface 161 provided around the center section, as viewed from the side.

[0067] The bearing 122 is provided in contact with the cam surface 161 of the cam 143. As Figure 8 As shown in (A), the bearing 122 is provided adjacent to a certain side (the right side of the servo motor 120) as viewed from the cam 143, and the bearing 122 is kept in contact with the cam surface 161 when the cam 143 is rotated in response to the rotation of the rotation shaft of the servo motor 120. The cam coupling plate 145 is connected to the bearing 122. The cam coupling plate 145 has one end connected to the bearing 122 and the other end fixed to the movable section 108. The coating needle holder fixed section 106 and the coating needle holder housing 104 are connected to the movable section 108. The coating needle holder housing 104 accommodates the coating needle holder 102.

[0068] The coating needle holder 102 includes the coating needle 24. The coating needle 24 is provided to protrude from the lower surface of the coating needle holder 20 (the lower side away from the side where the servo motor 120 is located). The coating liquid container 21 is provided below the coating needle holder 102. The coating needle 24 is held with the coating needle 24 put into the coating liquid container 21.

[0069] The movable section 108 is provided with a fixed pin 128B. Further, the frame holding the servo motor 120 is provided with a different fixed pin 128A. The spring 126 is installed to connect the fixed pins 128A, 128B. The spring 126 exerts a pulling force toward the coating liquid container 21 to the movable section 108. Further, the pulling force of the spring 126 acts on the bearing 122 via the movable section 108 and the cam coupling plate 145. This pulling force of the spring 126 keeps the bearing 122 pressed against the cam surface 161 of the cam 143.

[0070] Further, the movable section 108, the coating needle holder fixed section 106, and the coating needle holder housing 104 are connected to the linear guide 132 installed on the above-mentioned frame. The linear guide 132 is provided to extend in the Z-axis direction. This enables the movable section 108, the coating needle holder fixed section 106, and the coating needle holder housing 104 to move in the Z-axis direction.

[0071] Next, a description will be given of how the above-mentioned liquid material coating unit 4 operates. In the above-mentioned liquid material coating unit 4, the servo motor 120 is driven to rotate the rotation shaft of the servo motor 120, thereby rotating the cam 143. By this, the height of the cam surface 161 of the cam 143 in the Z-axis direction is changed so that the coating needle 24 is moved in the Z-axis direction. Figure 8The position of the bearing 122, which is in contact with the right cam surface 161 of the cam 143 shown in (A) along the Z-axis direction, also changes in response to the rotation of the drive shaft of the servo motor 120.

[0072] Subsequently, the movable section 108, the coating needle holder fixing part 106, and the coating needle holder housing 104 move along the Z-axis direction in response to the change in position of the bearing 122 along the Z-axis direction. This also causes the coating needle holder 102 held in the coating needle holder housing 104 to move along the Z-axis direction, thereby allowing the position of the coating needle 24 mounted in the coating needle holder 102 to change along the Z-axis direction.

[0073] Next, refer to Figure 8 A liquid material coating method using the liquid material coating apparatus 4 according to this embodiment is described.

[0074] Figure 8 This is a schematic diagram used to describe a liquid material coating method using a liquid material coating unit according to this embodiment. Figure 8 In the liquid material coating method shown, with Figure 8 (A) Figure 8 (B) Figure 8 (C) Figure 8 (D) and Figure 8 The (E) sequence of the operation steps. (Refer to...) Figure 8 First, such as Figure 2 As shown in (A), liquid material 100 is held inside a coating liquid container 21 of a liquid material coating unit 4 having a through hole 22 formed at the lowest part (bottom). Figure 8 The shape and size of the coating liquid container 21 shown are similar to Figure 8 The coating liquid container 21 shown is substantially the same. At least the distal end 23 of the coating needle 24 is immersed in the liquid material 100. The area of ​​the coating needle 24 immersed in the liquid material 100 may include the area located in... Figure 8 The portion shown above the distal end 23 and extending linearly with a uniform outer circumferential width. In this state, the coating liquid container 21 is along... Figure 8 The vertical direction is aligned with the bottom surface of the coated object 5, such as a groove-shaped component or a recessed component, on which the liquid material 100 is coated.

[0075] Next, as Figure 8As shown in (B), the coating liquid container 21 is brought close to the object to be coated 5. Specifically, the coating liquid container 21 is moved downwards. This causes at least a portion of the needle movement section 26 of the coating liquid container 21 to be surrounded by a side surface portion of the object to be coated 5. In other words, the needle movement section 26 partially enters a recessed portion of the object to be coated 5, thereby overlapping with the side surface portion of the object to be coated 5 in the horizontal direction. In other words, the needle movement section 26 partially enters a recessed portion of the object to be coated 5, thereby aligning the side surface portion of the object to be coated 5 with the vertical position of the needle movement section 26.

[0076] Next, as Figure 8 As shown in (C), the coating needle 24 moves along its extension direction, i.e., the up-down direction. That is, as... Figure 8 As shown in (C), the coating needle 24 moves downwards to bring the distal end 23 close to the bottom surface portion of the object to be coated 5. Figure 8 As shown in (D), this results in the liquid material 100 adhering to, for example, the distal end 23 of the coating needle 24, being applied to the bottom surface portion of the object 5 or the like. Note that at this time, as... Figure 8 As shown in (D), the coating needle 24 can also move downwards until its distal end 23 contacts the object to be coated 5. Alternatively, the coating needle 24 can move downwards until the liquid material 100 attached to the coating needle 24 contacts the object to be coated 5, without bringing the distal end 23 into contact with the object to be coated 5. In this case, the amount of protrusion P allowed for the coating needle 24 to protrude vertically from the through-hole 22 located at the lowest part of the coating liquid container 21 is greater than or equal to 1 mm and less than or equal to 3 mm, and this vertical direction is consistent with the extension direction of the coating needle 24.

[0077] After coating, the coating needle 24... Figure 8 As shown in (E), it moves upward. This causes the distal end 23 to retract back into the coating liquid container 21. During the coating process, preferably, the coating needle 24 extends towards the object to be coated 5 along the extension direction of the coating needle 24. Figure 8 (C) Figures 9 to 11 The movement of (D) and the distance of the coating needle 24 from the coating object 5 Figure 9 The reciprocating motion of (E) repeats 9 times per second or less. This allows for proper application of liquid material 100.

[0078] Next, refer to as needed Figure 9 The effects of this embodiment will be explained by comparing it with comparative examples.

[0079] Figure 9 This is a schematic diagram used to describe a liquid material coating method using a liquid material coating unit according to a comparative example. Figure 9 In China, with Figure 9 (A)Figure 9 (B) Figure 9 (C) and Figure 9 The (D) sequence of operations is executed. (Refer to...) Figure 9 ,like Figure 9 As shown in (A), compared to the coating liquid container 21 according to this embodiment, the first width w1 of the distal needle segment 26 of the coating liquid container 21 of the comparative example is larger, and the length t in the vertical direction is shorter. The first width w1 is greater than the lateral distance d across the side surface portion of the coating object 5. The first width w1 is greater than five times the second width w2. Therefore, the coating liquid container 21 of the comparative example cannot move downward to the position where the needle movement segment 26 is surrounded by the coating object 5. Therefore, as Figure 9 As shown in (B), with the position of the coating liquid container 21 remaining unchanged in the vertical direction, only the coating needle 24 moves downward and protrudes from the coating liquid container 21. Then, as... Figure 9 As shown in (C), liquid material 100 is applied to the object 5, and the coating needle 24 is as follows: Figure 8 As shown in (D), it moves upwards.

[0080] like Figure 9 As shown, since the coating liquid container 21 does not move downwards, therefore, with Figure 9 Compared to the embodiment shown, the protrusion amount p of the coating needle 24 needs to be increased. However, increasing the protrusion amount p of the coating needle 24 (e.g., 15 mm) will cause the following problems.

[0081] First, in coating Figure 9 As the coating needle 24 moves upwards, as shown in (D), air bubbles may become mixed into the liquid material 100 within the coating liquid container 21. This is due to the following reasons. Figure 9 (B) Figure 9 As shown in (C), the liquid material 100 is unevenly adhered to the portion of the coating needle 24 exposed as the needle moves downward. That is, on the outer periphery of the coating needle 24, areas with and without liquid material 100 alternate along the extending direction. This uneven adhesion is caused by the gap between the coating needle 24 and the liquid coating container 21 in the region near the through-hole 22 when the liquid material 100 is drawn by the coating needle 24 as it moves downward. When a portion of the side surface of the coating needle 24 without liquid material 100 returns to the liquid coating container 21, as... Figure 10As shown in (D) of FIG. 10, there is a possibility that air bubbles are mixed into the liquid material 100 in the coating liquid container 21. The greater the protruding amount p of the coating needle 24, the greater the number of regions to which the liquid material 100 is attached and regions to which the liquid material 100 is not attached alternately appear. Therefore, as the protruding amount p increases, the possibility of air bubbles being mixed in increases accordingly.

[0082] Further, the regions to which the liquid material 100 is not uniformly attached cause an increase in the variation in the coating diameter of the liquid material 100 to the coating object 5. Here, the coating diameter refers to the maximum value of the size of the liquid material 100 as viewed from above (for example, the major axis length of an ellipse), in other words, the coating diameter refers to the diameter of a virtual circle that surrounds the liquid material 100. This can cause the planar shape of the pattern formed by the liquid material 100 to be non-uniform.

[0083] On the other hand, when the protruding amount p in the coating needle 24 is very small (for example, less than 1 mm), another problem described below can occur. Figure 11 Figure 10 is a schematic view showing a coating process using a coating needle with a normal protruding amount. Figure 10 is a schematic view showing a coating process using a coating needle with a normal protruding amount. Figure 11 is a schematic view showing a coating process using a coating needle with a very small protruding amount, given for comparison with Figure 10 is a schematic view showing a coating process using a coating needle with a very small protruding amount, given for comparison with Figure 11 Figure 10 (A) of (D) and (E) of (D) show the state of the coating needle 24 before the coating process, Figure 11 (B) of (D) and (E) of (D) show the state of the coating needle 24 during the coating process, and Figure 10 (C) of (D) and (E) of (D) show the state of the coating needle 24 after the coating process. Figure 11 Figure 10 Figure 11 Figure 10 (A) of (D) and (E) of (D) show the state of the coating needle 24 before the coating process, Figure 11 (B) of (D) and (E) of (D) show the state of the coating needle 24 during the coating process, and Figure 10 (C) of (D) and (E) of (D) show the state of the coating needle 24 after the coating process. Figure 11 Figure 9 Figure 9 Figure 9 11 Figure 12 In the case of (D) and (E) of (D), the protruding amount of the coating needle 24 from the through-hole 22 located at the bottom of the coating liquid container 21 is very small, and compared to (D) and (E) of (D) in which the protruding amount is normal, the coating diameter of the liquid material 100 to be transferred to the coating object becomes too large. This is because, in (D) and (E) of (D), the distal end 23 of the coating needle 24 reaches the coating object 5 immediately after being exposed from the through-hole 22, so the amount of the liquid material attached to the distal end 23 becomes too large when the distal end 23 is exposed from the through-hole 22. Figure 13 Figure 12

[0084] ​​​​​​​​​​​​In view of the problems of the above-described comparative example, the liquid material coating unit 4 according to the present embodiment includes a coating needle 24 and a coating liquid container 21. The coating needle 24 coats the liquid material 100. The coating liquid container 21 holds the liquid material 100 therein and is formed with a through-hole 22 at a bottom portion that allows the coating needle 24 to pass therethrough. The coating liquid container 21 includes a joint section 25 and a needle movement section 26. The joint section 25 extends in a horizontal direction intersecting the extending direction of the coating needle 24. The needle movement section 26 extends from the joint section 25 to the through-hole 22 in a vertical direction coinciding with the extending direction of the coating needle 24. An amount of protrusion P of the coating needle 24 allowed to protrude from the through-hole 22 of the coating liquid container 21 in the vertical direction is greater than or equal to 1 mm and less than or equal to 3 mm. A first width Wl of the needle movement section 26 in the horizontal direction is less than or equal to 5 mm. A length of the needle movement section 26 extending from the joint section 25 to the through-hole 22 in the vertical direction is greater than or equal to 5 mm.

[0085] The above-described liquid material coating unit 4 and the liquid material coating apparatus 200 including the liquid material coating unit 4 can greatly reduce the air bubbles mixed in the liquid material 100 in the coating liquid container 21 by setting the amount of protrusion to an appropriately small amount, specifically, less than or equal to 3 mm. As shown in (D) of FIG. 10, the number of regions to which the liquid material 100 adheres and regions to which the liquid material 100 does not adhere, which alternately appear on the side surface of the coating needle 24, is reduced. When the coating needle 24 moves upward, this reduces the possibility that air generated by the gap between the regions to which the liquid material 100 does not adhere and the wall portion of the through-hole 22 is trapped in the coating liquid container 21. Thus, the above-described effects can be obtained. Figure 13 As shown in (D) of FIG. 10, the number of regions to which the liquid material 100 adheres and regions to which the liquid material 100 does not adhere, which alternately appear on the side surface of the coating needle 24, is reduced. When the coating needle 24 moves upward, this reduces the possibility that air generated by the gap between the regions to which the liquid material 100 does not adhere and the wall portion of the through-hole 22 is trapped in the coating liquid container 21. Thus, the above-described effects can be obtained.

[0086] Further, setting the amount of protrusion to an appropriately short amount, less than or equal to 3 mm, makes it possible to reduce the variation in the coating diameter of the liquid material 100 and to transfer a pattern having a uniform coating diameter. As shown in (D) of FIG. 10, the number of regions to which the liquid material 100 adheres and regions to which the liquid material 100 does not adhere, which alternately appear on the side surface of the coating needle 24, is reduced. This is because the influence of the liquid material 100 adhering unevenly on the transferred pattern of the liquid material 100 is reduced. Figure 12 As shown in (D) of FIG. 10, the number of regions to which the liquid material 100 adheres and regions to which the liquid material 100 does not adhere, which alternately appear on the side surface of the coating needle 24, is reduced. This is because the influence of the liquid material 100 adhering unevenly on the transferred pattern of the liquid material 100 is reduced.

[0087] Further, setting the amount of protrusion to an appropriately short amount, less than or equal to 3 mm, makes it possible to reduce the variation in the coating diameter of the liquid material 100 and to transfer a pattern having a uniform coating diameter. As shown in (D) of FIG. 10, the number of regions to which the liquid material 100 adheres and regions to which the liquid material 100 does not adhere, which alternately appear on the side surface of the coating needle 24, is reduced. This is because the influence of the liquid material 100 adhering unevenly on the transferred pattern of the liquid material 100 is reduced.

[0088] Furthermore, setting an appropriate protrusion length of less than or equal to 3 mm reduces the loss of liquid material 100. It is difficult to use liquid material 100 that is non-uniformly adhered to the side surface of the coating needle 24 for subsequent transfer to the coating object 5. Therefore, reducing the protrusion length and the amount of non-uniformly adhered liquid material 100 reduces the amount of liquid material 100 not used for transfer.

[0089] By setting the first width of the needle movement section 26 in the horizontal direction to less than or equal to 5 mm, and setting the length of the needle movement section 26 extending from the connecting section 25 in the vertical direction to greater than or equal to 5 mm, the effect of appropriately reducing the protrusion amount can be obtained. Therefore, when the coating object 5 has a groove shape or a recessed shape, the needle movement section 26 can be positioned to be surrounded by the side surface portion of the coating object 5, and the coating liquid container 21 can be brought close to the bottom surface portion of the coating object 5. That is, the needle movement section 26 is at least partially inserted to fit into the side surface portion of the coating object 5, such as a groove shape. This makes the distance between the bottom surface portion of the coating object 5 and the lowermost portion of the needle movement section 26 equal to the length suitable for coating. Note that, as described above, the length T of the needle movement section 26 in the vertical direction is more preferably greater than or equal to 5 mm. However, the length T only needs to be greater than the size obtained by subtracting the protrusion amount P of the coating needle 24 (e.g., 3 mm) from the depth of the side surface portion of the coating object 5 in the vertical direction. Therefore, the above-mentioned effects can be achieved.

[0090] Furthermore, setting an appropriate protrusion length greater than or equal to 1 mm reduces the amount of liquid material 100 adhering to the distal end 23 of the coating needle 24 and allows for the coating of fine patterns.

[0091] When the liquid material 100 is transferred to the bottom surface portion located at the bottom of the side surface portion having a groove shape or a recessed shape of the coating object 5, features such as the shape and size of the coating liquid container 21 of the liquid material coating unit 4 according to this embodiment are particularly effective.

[0092] In the liquid material coating unit 4 described above, the first width W1 in the horizontal direction is preferably less than or equal to five times the second width W2 of the portion of the coating needle 24 extending in the vertical direction. Therefore, the same effect as described above can be obtained.

[0093] The liquid material coating method according to the present embodiment includes the following processes. The coating liquid container 21 having the through-hole 22 formed at the bottom is aligned with the coating object 5 of the liquid material 100, where the liquid material 100 is held in the coating liquid container 21, and the distal end 23 of the coating needle 24 is immersed in the liquid material 100. The coating liquid container 21 is brought close to the coating object 5. The coating needle 24 is moved in the extension direction of the coating needle 24 to coat the liquid material 100 to the coating object 5. In the above-mentioned coating process, the protruding amount P of the coating needle 24 protruding from the through-hole 22 of the coating liquid container 21 in the extension direction is allowed to be greater than or equal to 1 mm and less than or equal to 3 mm. In the above-mentioned approaching process, the coating liquid container 21 is placed so as to be at least partially surrounded by the coating object 5. Thus, the same effects as described above can be obtained.

[0094] For the liquid material coating method, the liquid material 100 is preferably a liquid having fine particles suspended therein. The liquid material 100 containing fine particles is poor in elasticity and is easily broken, and thus it is highly likely that the uneven adhesion to the side surface of the coating needle 24 as shown in (B) to (D) of FIG. 10 occurs. The liquid material coating method according to the present embodiment is particularly effective in a case where the same effects and advantages as described above can be produced using such a liquid material 100. Figure 13

[0095] For the liquid material coating method, the viscosity of the liquid material is preferably less than or equal to 13.10 Pa s (Pascal second). When the viscosity of the liquid material 100 is too high, it is difficult to separate the liquid material 100 located between the coating needle 24 and the coating object 5 at the time of starting the ascent after the coating, due to a large amount of the liquid material 100 adhering to the distal end 23 of the coating needle 24. As described above, reducing the viscosity can reduce the likelihood of such a problem occurring.

[0096] First Working Example

[0097] A test of weighing the bubble mixing ratio was performed in the case of various changes in the protruding amount P. The test was performed in the case where the protruding amount P of the coating needle 24 from the coating liquid container 21 was set to 15 mm and the protruding amount P was set to 3 mm. The liquid material 100 was a polymer solution. As the liquid material 100, three types of liquid material having a viscosity of 0.45 Pa s (indicated as "A"), a liquid material having a viscosity of 1.95 Pa s (indicated as "B"), and a liquid material having a viscosity of 13.10 Pa s (indicated as "C") were used. Forty-eight samples were prepared for each type, and the same test was performed for each sample.

[0098] ​Table 1 below shows the test results in the case where the distal end 23 of the coating needle as the coating needle 24 is not tapered and the cross section intersecting the direction of extension is circular with a first width Wl equal to 1000 μm (hereinafter referred to as "first coating needle").

[0099] [Table 1]

[0100]

[0101] Further, Table 2 below shows the test results in the case where a coating needle is used as the coating needle 24 (hereinafter referred to as "second coating needle") in which the portion other than the distal end 23 has a circular shape with a first width Wl equal to 1000 μm as described above, the distal end 23 is tapered, and the cross section intersecting the direction of extension of the lowermost portion has a circular shape with an outer diameter (corresponding to Wl described above) equal to 800 μm.

[0102] [Table 2]

[0103]

[0104] From Tables 1 and 2, it is seen that regardless of the type of coating needle 24, the probability of mixing in bubbles is high when the protrusion amount P is 15 mm, and the mixing in of bubbles is completely prevented when the protrusion amount P is 3 mm. The higher the viscosity of the liquid material 100 is when the protrusion amount is 15 mm, the higher the bubble mixing ratio is. On the other hand, when the protrusion amount is 3 mm, even in the example of the highest viscosity of 13.10 Pa-s, bubbles are not mixed in at all. It is thus seen that when the viscosity is less than or equal to 13.10 Pa-s, the mixing in of bubbles is completely prevented in the case where the protrusion amount is set to 3 mm.

[0105] Further, in the above tests, the variation in the coating diameter of the liquid material 100 was examined. Figure 2 is a graph showing the test results of the variation in the coating diameter in the case where the protrusion amount is set to 3 mm. 0.5 mm below the liquid surface is a graph showing the test results of the variation in the coating diameter in the case where the protrusion amount is set to 15 mm. In each graph, "Φ800 μm" indicates the results of the second coating needle, and "Φ1000 μm" indicates the results of the first coating needle. The calculation results of the variation coefficient (3σ / Ave.) obtained from Liquid surface height and 0.5 mm above the liquid surface are shown in Table 3 below.

[0106] [Table 3]

[0107]

[0108] Referring to Number of samples , Number of mixed bubblesand Table 3, the following results were obtained. When the protruding amount was 15 mm, the variation coefficient varied between the liquid materials 100 having different viscosities, i.e., between A, B, and C, and also varied between the liquid materials 100 having the same viscosity. Further, when the protruding amount was 15 mm, the absolute value of the variation coefficient increased. On the other hand, when the protruding amount was 3 mm, the variation coefficient varied little between the liquid materials 100 having different viscosities, i.e., between A, B, and C, and also varied little between the liquid materials 100 having the same viscosity. Further, when the protruding amount was 3 mm, the variation coefficient varied little. There was no significant difference between the case where the first coating needle was used and the case where the second coating needle was used.

[0109] As described above, compared with the case where the protruding amount was 15 mm, setting the protruding amount to 3 mm resulted in little variation in the coating diameter. This is presumably because, compared with the case where the protruding amount was 15 mm, setting the protruding amount to 3 mm resulted in little variation in the amount of the liquid material 100 adhering to the side surface of the coating needle 24, and the liquid material 100 could thus be stably coated.

[0110] Second Working Example

[0111] As described above, reducing the protruding amount P of the coating needle 24 from the through-hole 22 of the coating liquid container 21 in the coating process (see Fig. 1) makes it possible to reduce the number of air bubbles mixed into the liquid material 100 in the coating liquid container 21. This allows a pattern having a minute coating diameter to be stably supplied. Bubble mixing ratio ) makes it possible to reduce the number of air bubbles mixed into the liquid material 100 in the coating liquid container 21. This allows a pattern having a minute coating diameter to be stably supplied.

[0112] However, when the amount of the liquid material 100 in the coating liquid container 21 is small, air bubbles can be mixed into the liquid material 100 in the coating liquid container 21. This is presumably because, when the coating needle 24 moves upward to retract into the coating liquid container 21, the tip end of the coating needle 24 (the lowermost part of the distal end 23) separates upward from the liquid surface of the liquid material 100 in the coating liquid container 21, and, when the coating needle 24 moves downward again, the tip end of the coating needle 24 traps air. Even in the early stage of the coating process, in the case where the amount of the liquid material 100 in the coating liquid container 21 does not significantly decrease, this can reduce the use efficiency of the liquid material 100, because the air bubbles mixed into the liquid material 100 prevent the liquid material 100 from being sufficiently coated. In the present working example, the results of investigating a method of adjusting the configuration of the liquid material coating unit for the cause of air bubble mixing will be described. In the following description, unless otherwise specified, the liquid surface of the liquid material 100 refers to the liquid surface on the upper side of the liquid material 100 (the uppermost part of the liquid material 100) in the vertical direction.

[0113] According to the first working example, the same liquid material as the liquid material "C" having a viscosity of 13.10 Pa-s was used to check whether air bubbles were mixed in when the initial position of the coating needle 24 in the vertical direction was changed with respect to the position of the liquid surface of the liquid material 100 in the coating liquid container 21. Table 4 below shows the results of the check. Note that the initial position of the coating needle 24 refers to the first vertical position of the coating needle 24 before the coating needle 24 starts to move downward to perform the coating process (initial state).

[0114] [Table 4]

[0115] Figure 14 Figure 14 Figure 14 Figure 15 24 24 24 Figure 15 0 8 23 Figure 15 0％ 33％ 96％

[0116] Table 4 shows that air bubbles can be generated in the liquid material 100 when the tip of the coating needle 24 is placed above the liquid surface of the liquid material 100 in the initial state, i.e., the coating needle 24 is not immersed in the liquid material 100 at all. Therefore, it is necessary to set the initial position of the coating needle 24 so that the tip of the coating needle 24 is as low as possible with respect to the liquid surface of the liquid material 100. Specifically, when the amount of the liquid material 100 is small, and the liquid surface is lowered, it is important to adjust the initial position of the coating needle 24.

[0117] Figure 15 is a schematic view showing the initial position of the coating needle in the vertical direction in the coating liquid container. Referring to Figure 15 , the coating needle 24 includes a distal end 23 that is inclined due to tapering or the like as shown in Figure 15 , and a uniform width region 24a other than the distal end 23. The uniform width region 24a is a region above the distal end 23, and where the maximum width of the outer periphery is substantially uniform in the vertical direction. The maximum width of the outer periphery of the uniform width region 24a is W2.

[0118] The inner wall 21a of the coating liquid container 21 has a tapered shape on the lower side, where the dimension of the inner wall 21a in the left-right direction in the figure, i.e., the area of the cross section in the horizontal direction, is smaller than the dimension on the upper side. The initial position of the coating needle 24 is the position of the tip of the coating needle 24 in the vertical direction with respect to the lowermost part O of the through-hole 22 of the coating liquid container 21, and is represented as a distance P0. The distance P0 is set to be greater than the length t of the through-hole 22 in the vertical direction at the lower part of the coating liquid container 21. When the coating needle 24 is retracted into the coating liquid container 21, the liquid material 100 flows around and into the region adjacent to the tip of the coating needle 24 in the coating liquid container 21 (the region directly below the tip of the coating needle 24).

[0119] However, when the distance P0 in the vertical direction between the lowermost portion of the through-hole 22 and the tip of the application needle 24 is small at the initial position of the application needle 24, the liquid material 100 is difficult to flow into the region adjacent to the tip of the application needle 24, and the time required for the flow-in becomes longer. Since the time required for the flow-in becomes longer, the so-called "application interval" is set longer, and the cycle time of the application process in which the application needle 24 applies the liquid material 100 becomes longer. Therefore, the initial position of the application needle 24, that is, the above-described distance P0, is empirically set to be larger than the length t of the through-hole 22 in the vertical direction. However, the design criteria of the distance P0 are not clear. Therefore, in the present working example, a method by which the initial position of the application needle 24 (distance P0) can be made as short as possible by controlling the void ratio of the "gap position" and the tip of the application needle 24 is made as low as possible with respect to the liquid surface of the liquid material 100 is verified. Specifically, a method by which the initial position of the lowermost portion of the distal end 23 of the application needle 24 is set at a position at which the distal end 23 is placed in the liquid material 100 and covered with the liquid material 100 is verified. The case in which the distance P0 is smaller than t will also be studied below.

[0120] Figure 16 is a schematic view for describing the gap position. Referring to Figure 15 , the gap position P1 refers to Figure 16 the position in which the distance in the left-right direction (horizontal direction) intersecting the extension direction of the application needle 24 between the application needle 24 and, in particular, the inner wall of the through-hole 22 of the application liquid container 21 is the smallest among the respective initial positions of the application needle 24 in the vertical direction in the initial state. Here, the application needle 24 located at the gap position P1 can be the distal end 23 having an outer periphery that forms a tapered shape. The gap position P1 is defined in the region of the lowermost portion of the through-hole 22 located above the region in which the C-shaped surface 27 is formed in Figure 16 . Generally, as Figure 16As shown, the distance in the left-right direction between the outer periphery of the distal end 23 of the coating needle 24 and the wall surface of the through hole 22 is smaller than the distance in the left-right direction in other regions. In this case, the gap position P1 is located at the uppermost part of the through hole 22. This is because the outer periphery of the distal end 23 of the coating needle 24 gradually increases from the end along a tapering shape, and the diameter Td of the end of the coating needle 24 at the gap position P1 is larger than the diameter Pd of the end of the coating needle 24 (note that the diameter Td is smaller than the diameter Hd of the through hole 22). In the region above the through hole 22, the dimension in the left-right direction of the inner wall 21a of the liquid coating container 21 is significantly larger than the dimension in the left-right direction of the through hole 22. Therefore, in the region above the through hole 22, the distance between the outer periphery of the distal end 23 and the inner wall 21a of the liquid coating container 21 does not become minimum. Therefore, the diameter Td becomes maximum exactly next to the through hole 22, which is usually the uppermost part of the through hole 22. Note that in Figure 16 In the middle, the distal end 23 is positioned vertically at the uppermost part of the through hole 22, or alternatively, the uniform width region 24a can be positioned at that location.

[0121] Figure 16 It is along Figure 15 A schematic cross-sectional view cut along line XVI-XVI. That is, Porosity The cross-section at gap location P1 along the vertical direction is shown. Therefore, Coating interval (ratio) This is a schematic diagram used to describe porosity. (Refer to...) Figure 8 Porosity refers to the porosity of a plane along the horizontal direction of the aforementioned gap position P1. Figure 8 On the given paper plane, the porosity is the ratio of the area of ​​the void region excluding the portion where the coating needle (distal end 23) is placed to the area of ​​the region surrounded by the inner wall 21a (through hole 22) of the coating liquid container 21. In other words, the porosity is the ratio of the area of ​​the void region 28 between the outermost part of the distal end 23 and the inner wall (through hole 22) to the area of ​​the void region 28. Figure 17 The part inside (through hole 22) corresponds to Figure 17 The ratio of the area of ​​the region of the inner wall 21a.

[0122] In this working example, a liquid material with the same viscosity as liquid material "C" having a viscosity of 13.10 Pa·s is used to verify the effect of changing the porosity on the coating interval. Note that the coating interval refers to the time from the moment the coating needle 24 moves upward after coating until immediately before the coating needle 24 begins to move downward to perform coating again. The coating interval is determined as the time required to compare the first coating diameter of the pattern coated in the first coating step with the second coating diameter of the pattern coated immediately after the first coating step in the second coating step, and to make the difference within 5% of the first coating diameter.

[0123] Typically, the coating diameter tends to be smaller when the coating interval is shorter than the time it takes for the liquid material 100 to flow into the region adjacent to and directly below the end of the coating needle 24 in the coating liquid container 21. When the porosity is 80%, the coating interval is defined as a reference value of 1, and the change in coating interval with varying porosity is calculated. Table 5 below shows the calculation results. In Table 5, when the rate of change in coating interval is less than 5% with a porosity of 80% (i.e., when the coating interval is greater than or equal to 0.95 and less than or equal to 1.05), the coating interval is described as 1 (no change).

[0124] [Table 5]

[0125] Figure 17 Figure 17 80％ 1 71％ 1 62％ 1 43％ 1.6 29％ 2.8

[0126] As shown in Table 5, a lower porosity results in a longer coating interval. In other words, a lower porosity indicates a lower position for the coating needle 24. This is because, with the distal end 23 at the same height as the uppermost part of the through-hole 22, the diameter Td of the coating needle 24 at the same height as the uppermost part of the through-hole 22 increases as the coating needle 24 moves downward. Therefore, by lowering the initial position of the coating needle 24 to make the porosity less than or equal to, for example, 43%, the number of incorporated air bubbles can be reduced, as shown in Table 4. This is because when the porosity is less than or equal to 43%, compared to the case of a porosity of 80%, the end of the coating needle 24 is relatively lower in the liquid material 100 at the initial position, and the coating needle is correspondingly fully immersed in the liquid material 100. However, in this case, as shown in Table 5, a longer coating interval results in a longer cycle time, which makes the utilization efficiency of the liquid material lower.

[0127] Therefore, as shown in Table 5, before the coating process, the coating liquid container 21 is aligned with the coating object 5 of the liquid material 100 (e.g., ...). Figure 17 As shown in (A), this makes the coating interval as close as possible to the reference value. More preferably, the initial position of the coating needle 24 is determined to minimize the porosity within a porosity range where the coating interval does not change relative to the reference value (when the porosity is 80%, even if the coating interval changes relative to the reference value, the change falls within 5% of the reference value). Specifically, in... Figure 17In the alignment process shown in (A), the initial position of the coating needle 24 is preferably determined to be a position with a porosity greater than or equal to 62% (60%). When the initial position of the coating needle 24 is lowered to a position with a porosity of, for example, 62% (60%), the coating needle 24 is located at a lower position than the initial position of the coating needle 24 in the case of a porosity of 80%. Therefore, it is more preferable to lower the initial position of the coating needle 24 to a position with a porosity of 62% (60%), because the number of air bubbles mixed in as shown in Table 4 can be reduced, and the increase in coating interval as shown in Table 5 can be suppressed. Therefore, when the porosity is 62% (60%), the cycle time of the coating process can be suppressed while reducing the number of air bubbles mixed in. As described above, compared with known empirical methods, using an adjustment method that minimizes the coating interval allows for increased utilization efficiency of the liquid material 100 and minimizes the coating interval.

[0128] Note that when the coating needle 24 has a large end diameter Pd and a highly viscous liquid material 100 is used, air bubbles can be prevented when the coating needle 24 is placed in the preferred initial position found in this working example, but the coating interval may become longer. In this case, design factors such as the internal shape of the coating liquid container 21, the diameter Hd of the through-hole 22 of the coating liquid container 21, and the shape of the coating needle 24 can be optimized. Therefore, the space near the end of the coating needle 24 at the initial position can be designed to be larger to allow the liquid material 100 to flow more easily into the space near the end of the coating needle 24. This allows for an increase in the effect of shortening the cycle time of the coating process without introducing air bubbles.

[0129] Third working example

[0130] The second working example illustrates a method to prevent the coating gap from increasing while paying attention to the gap position P1. However, when the coating gap becomes shorter, air bubbles may mix into the liquid material 100 in the coating liquid container 21. Figure 18 This is a schematic diagram illustrating how air bubbles are incorporated according to the coating interval. Figure 18 by Figure 8 (A) Figure 1 (B) and Figure 8 The order of (C) shows the change over time. (See reference...) Figure 8When the application needle 24 is retracted into the application liquid container 21, the liquid material 100 flows into a region adjacent to the tip of the application needle 24 in the application liquid container 21. However, when the application interval is short, the application needle 24 enters the application liquid container 21, and the region adjacent to the tip of the application needle 24 is not sufficiently filled with the liquid material 100. At this time, air in the region adjacent to the tip of the application needle 24 that is not sufficiently filled with the liquid material 100 is trapped in the liquid material 100. When such a problem occurs, it is considered preferable to increase the application interval time.

[0131] Figure 8 is a flowchart of a liquid material application method according to a third working example. Referring to Figure 8 In the present working example, the application process of causing the application needle 24 to apply the liquid material 100 is performed multiple times. That is, the application process includes a first application process (S10) of causing the application needle 24 to apply the liquid material 100, and a second application process (S20) of causing the application needle 24 to apply the liquid material 100 again immediately after the first application process.

[0132] Between the first application process (S10) and the second application process (S20), as shown in (E) of Figure 8 , the application needle 24 is moved upward away from the application object 5 (S11). This causes the entire application needle 24 including the tip to be retracted into the application liquid container 21. The application liquid container 21 can be moved upward simultaneously with or immediately after the retraction. Immediately after the retraction, a horizontal movement process (S12) of relatively moving the application needle 24 in the horizontal direction to a position at which the liquid material 100 is to be applied in the second application process. That is, the application object 5 is moved on, for example, the X-axis stage 1 and the Y-axis stage 2 (see ​ ) so that the application object 5 to be applied by the application needle 24 next is positioned directly below the liquid material application unit 4. Alternatively, the application needle 24 can be moved in the direction of the XY plane to be positioned directly above the application object 5 to be applied next. This aligns the application liquid container 21 with the application object 5 of the liquid material 100.

[0133] Further, a waiting process (S13) of causing the application needle 24 to wait in the application liquid container 21 is provided between the first application process (S10) and the second application process (S20). Specifically, the time during which the application needle 24 waits in the application liquid container 21 refers to a time during which the stage such as the X-axis stage 1 and the application liquid container 21 do not move, the application needle 24 does not move up and down relative to the application liquid container 21, and the application needle 24 remains stationary in the application liquid container 21. In the present working example, such a waiting time of the application needle 24 is provided for the process (S13). Subsequently, the application liquid container 21 is brought close to the application object 5 (S14). That is, for example, as shown in ​As shown in (B) of FIG. 10, the coating liquid container 21 moves downward. Subsequently, as shown in (C) of FIG. 10, the coating needle 24 moves downward with respect to the coating liquid container 21, and as shown in (D) of FIG. 10, the distal end 23 of the coating needle 24 contacts the coating object 5. The second coating process (S20) is performed as shown in (E) of FIG. 10. ​ As shown in (C) of FIG. 10, ​ As shown in (D) of FIG. 10, the distal end 23 of the coating needle 24 contacts the coating object 5. The second coating process (S20) is performed as shown in (E) of FIG. 10. ​ As shown in (C) of FIG. 10, ​ As shown in (D) of FIG. 10, the distal end 23 of the coating needle 24 contacts the coating object 5. The second coating process (S20) is performed as shown in (E) of FIG. 10.

[0134] As described above, in the present working example, in addition to the processes (Sll), (S12), (S14), a waiting process (S13) of making the coating needle 24 wait in the coating liquid container 21 is provided between the first coating process (S10) and the second coating process (S20). This process (S13) can be temporarily performed before or after the horizontal movement process (S12). The coating interval in the present working example is obtained by adding the time of the waiting process (S13) of making the coating needle 24 wait in the coating liquid container 21 to the coating interval in the second working example. That is, the coating interval in the present working example refers to the time from immediately after the coating in the first coating process (S10) to the start of the downward movement of the coating needle 24 in the second coating process (S20) after the upward movement of the entire coating needle 24 to retract the entire coating needle 24 into the coating liquid container 21.

[0135] The adjustment method of the present working example is particularly effective when the distance (interval) in the horizontal direction between the coating position in the first coating process (S10) and the coating position in the second coating process (S20) is short. Further, the adjustment method of the present working example is particularly effective when the movement time of the stage such as the X-axis stage 1 and the Y-axis stage 2 in the horizontal movement process (S12) is short.

[0136] Next, the experimental details and results of the present working example will be described. In the case where the coating interval was varied, the bubble mixing ratio was tested using the same liquid material as the liquid material "A" having a viscosity of 0.45 Pa-s, the liquid material "B" having a viscosity of 1.95 Pa-s, and the liquid material "C" having a viscosity of 13.10 Pa-s. The variation of the coating interval was adjusted according to the presence or absence of the waiting process (S13) of making the coating needle 24 wait in the coating liquid container 21 and the change over time. Table 6 below shows the test results.

[0137] [Table 6]

[0138]

[0139] As shown in Table 6, in the case of A, which has a low viscosity, no bubbles were mixed in for a short coating interval of 1 second (i.e., in the example in which the waiting process (S13) in which the coating needle 24 waits in the coating liquid container 21 is not performed). However, in the case of B, which has a high viscosity, the bubble mixing ratio was higher than that of A for a short coating interval of 1 second. The bubble mixing ratio of C, which has an even higher viscosity, was higher than that of B. It can be inferred that, since A has a low viscosity, the liquid material 100 flows easily, and, after the coating needle 24 is retracted into the coating liquid container 21, the liquid material 100 fills the area just below the tip of the coating needle 24, thereby preventing bubbles from being mixed in. However, even in the case of B and C, which have high viscosities, increasing the coating interval and providing the waiting process (S13) reduces the bubble mixing ratio. When the coating interval is 3 seconds, the bubble mixing ratio is 13% in the case of C, which has the highest viscosity, whereas, when the coating interval is 5 seconds, the bubble mixing ratio is 0% even in the case of C. Note that, in the case of a coating interval of 3 seconds, the waiting time of the coating needle 24 is 2 seconds. In the case of a coating interval of 5 seconds, the waiting time of the coating needle 24 is 4 seconds. This indicates that a higher viscosity requires a longer coating interval time (the waiting time of the coating needle 24 in the process (S13)) to prevent bubbles from being mixed in.

[0140] Note that the polymer solution as the liquid material 100 has complex flow characteristics depending on the type, and, even at the same viscosity, has different fluid behaviors depending on the presence or absence of thixotropy and stringiness. When setting the coating interval, it is preferable to set the coating interval in accordance with the test results of Table 6, and to appropriately consider the flow characteristics of the liquid material 100 to be used.

[0141] The features described in each example and each working example included in the embodiments can be appropriately combined and applied within the scope without technical contradiction. For example, the features derived in the second working example and the features derived in the third working example can be combined. The features included in the present embodiments can be applied to each of the first to third working examples.

[0142] It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in all respects. The scope of the present invention is defined by the claims rather than the description above, and the present invention is intended to include all modifications within the scope of the claims, the equivalents of the claims, and the scope.

[0143] List of Reference Signs

[0144] 1: X-axis stage, 2: Y-axis stage, 3: Z-axis stage, 4: liquid material coating unit, 5: coating object, 6: observation optical system, 7: CCD camera, 8: control panel, 9: monitor, 10: control computer, 11: controller, 12: base, 21: coating liquid container, 21a: inner wall, 22: through-hole, 23: distal end, 24: coating needle, 24a: uniform width region, 25: linking section, 26: needle movement section, 27: C-shaped surface, 28: gap, 100: liquid material, 102: coating needle holder, 104: coating needle holder housing, 106: coating needle holder fixing section, 108: movable section, 110: coupling shaft, 112: coupling plate, 114: eccentric shaft, 116: eccentric plate, 118: origin sensor, 120: servo motor, 121: motor driver, 122, 124: bearing, 126: spring, 128, 128A, 128B: fixing pin, 130: linear motion mechanism, 132: linear guide, 143: cam, 145: cam coupling plate, 161: cam surface, 162: upper end flat region, 163: lower end flat region, 200: liquid material coating apparatus.

Claims

1. A liquid material coating unit, the liquid material coating unit comprising: A coating needle for coating liquid materials; as well as A coating liquid container holds the liquid material therein and has a through-hole formed at the bottom to allow the coating needle to pass through. The coating liquid container includes a connecting section and a needle movement section. The connecting section extends in a horizontal direction intersecting the extension direction of the coating needle, and the needle movement section extends vertically from the connecting section to the through-hole, the vertical direction being consistent with the extension direction of the coating needle. The coating needle is allowed to protrude from the through-hole of the coating liquid container by an amount greater than or equal to 1 mm and less than or equal to 3 mm along the vertical direction. The first width of the needle movement section along the horizontal direction is less than or equal to 5 mm, and The length of the needle movement section extending from the connecting section to the through hole along the vertical direction is greater than or equal to 15 mm.

2. The liquid material coating unit as described in claim 1, characterized in that, The first width along the horizontal direction is less than or equal to five times the second width of a portion of the coating needle extending along the vertical direction.

3. A liquid material coating apparatus, the liquid material coating apparatus comprising: The liquid material coating unit as described in claim 1 or 2; as well as A base set on the floor surface.

4. A method for coating a liquid material, the method comprising: An alignment process in which a coating liquid container having a through hole formed at the bottom is aligned with a coating object of liquid material, wherein the liquid material is held in the coating liquid container and the distal end of a coating needle is immersed in the liquid material. The process of bringing the coating liquid container close to the object to be coated; and A coating process in which the liquid material is applied to the object by moving the coating needle along its extension direction, wherein... The coating liquid container includes a connecting section and a needle movement section. The connecting section extends in a horizontal direction intersecting the extension direction of the coating needle, and the needle movement section extends vertically from the connecting section to the through-hole, the vertical direction being consistent with the extension direction of the coating needle. In the coating process, the coating needle is allowed to protrude from the through-hole of the coating liquid container by an amount greater than or equal to 1 mm and less than or equal to 3 mm along the extension direction. In the approach step, the coating liquid container is positioned such that it is at least partially surrounded by the object to be coated. The first width of the needle movement section along the horizontal direction is less than or equal to 5 mm, and The length of the needle movement section extending from the connecting section to the through hole along the vertical direction is greater than or equal to 15 mm.

5. The liquid material coating method as described in claim 4, characterized in that, A porosity is defined at the location where the distance between the coating needle and the inner wall of the coating liquid container is shortest in the horizontal direction. The porosity represents the ratio of the area excluding the portion where the coating needle is placed to the area surrounded by the inner wall of the coating liquid container on a plane extending in a horizontal direction intersecting the extension direction of the coating needle. In the alignment process, the coating needle is positioned such that the distal end of the coating needle is positioned along the extension direction in a manner that aligns with a porosity greater than or equal to 60%.

6. The liquid material coating method as described in claim 4 or 5, characterized in that, The viscosity of the liquid material is less than or equal to 13.10 Pa·s.

7. The liquid material coating method as described in claim 4 or 5, characterized in that, In the coating process, the movement of the coating needle toward the object to be coated and the movement of the coating needle away from the object to be coated along the extension direction are repeated 9 times or less per second.

8. The liquid material coating method as described in claim 4 or 5, characterized in that, The coating process includes a first coating process in which the coating needle applies the liquid material, and a second coating process in which the coating needle applies the liquid material again immediately after the first coating process. Between the first coating process and the second coating process, a horizontal movement process is performed to move the coating needle relative to the position where the liquid material is to be coated in the second coating process along a horizontal direction intersecting the extension direction, a waiting process to wait the coating needle in the coating liquid container, and the approach process.

9. The liquid material coating method as described in claim 4 or 5, characterized in that, The liquid material is a liquid containing fine particles suspended therein.

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