JP2013148408A - Clearance measuring method, clearance device, application method, and application device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an application device and an application method capable of obtaining a uniform and high-quality application film having no unevenness by applying liquid while accurately adjusting a clearance on the basis of a clearance value measured during the application.SOLUTION: In a clearance measuring method for measuring a clearance C between a discharge port surface 2g including an application liquid discharge port of an application unit 2s and a surface 9a to be applied of a member 9 to be applied arranged oppositely to the discharge port, a real image of an end part of the discharge port surface 2g and a reflection image 2ji of an end part 2j of the discharge port surface 2g on the surface 9a to be applied of the member 9 to be applied are captured, and the clearance C between the discharge port surface 2g of the application unit 2s and the surface 9a to be applied of the member 9 to be applied is calculated on the basis of a length between the captured real image of the end part 2j of the discharge port surface 2g and the reflection image of the end part 2j of the discharge port surface 2g.

Description

    The present invention relates to a gap measuring method and a gap measuring device between a coating device and a member to be coated, such as a die coater that coats while maintaining a gap between the coating device and a member to be coated at a predetermined constant value with high accuracy, and a gap therebetween. The present invention relates to a coating method and a coating apparatus based on a measurement result.

    One example of the necessity of a coating process while controlling the gap between the coating device and the member to be coated with high accuracy is a manufacturing process of a plasma display (hereinafter referred to as PD). Since PDs can be made larger, thinner, and lighter than CRTs, television receivers using these are widely used. A typical PD includes a glass substrate (back plate panel) having phosphor layers for red, green, and blue formed in stripes by partition walls, and a glass substrate (front plate panel) formed with scanning electrodes. ) And a plasma display panel (hereinafter referred to as PDP).

    As a method for forming the partition walls of the back panel of such a PDP, a coating film is formed by applying a partition paste to a single glass substrate, and after drying, a method such as sandblasting or photolithography is used. Some are formed in a stripe or lattice pattern with a predetermined pitch and fired. Although the thickness of the coating film is relatively thick after baking, about 100 to 200 μm, the uniformity of the thickness affects the image characteristics of the PDP, so it is important to uniformly apply the barrier rib paste. There are various coating methods, and one of them is a die coating method using a die coater (for example, Patent Document 1). In this die coating method, the partition paste is discharged from the die while relatively moving the die and the glass substrate while keeping the gap between the die corresponding to the applicator and the glass substrate corresponding to the member to be coated at a predetermined constant value. And apply to a glass substrate.

    In the die coating method, in order to obtain a stable and uniform coating film, it is important to maintain the gap between the die and the glass substrate at a predetermined constant value with high accuracy. Therefore, it is necessary to accurately measure the gap between the die and the glass substrate at a position where the coating is actually performed to confirm that the distribution is a predetermined constant value and a uniform distribution.

For this purpose, light is incident obliquely on the substrate surface, and after repeated incidence and reflection between the tip of the discharge nozzle corresponding to the substrate and the die, the position between the substrate and the discharge nozzle is determined from the light receiving position and the light incident angle. There is a method of directly measuring the gap. (For example, Patent Document 2)
However, with this method, when light hits the slit or hole at the tip of the discharge nozzle, the light enters the inside of the nozzle and the reflected light cannot be obtained or diffusely reflected, and it is not possible to accurately measure the gap. Have difficulty.

    As another method, there is a method of irradiating a laser beam perpendicular to the gap between the surface of the substrate and the applicator and measuring the gap between the substrate surface and the applicator based on the amount of received laser light (for example, Patent Document 3).

    However, with this method, it is difficult to accurately measure the gap due to diffraction of laser light passing through the gap.

    As described above, as for the means for accurately measuring the gap between the die and the glass substrate at the actual application position, there is actually no effective known means.

JP-A-6-339656 (5th column 18th line to 7th column 25th line, FIG. 1, FIG. 2, FIG. 3) JP 09-17393 (Claim 1, FIG. 1) JP-A-2004-139814 (Claim 3, fifth column, 42nd line to sixth column, 21st line, FIG. 2)

    The object of the present invention is to be able to accurately measure the gap between the discharge port surface including the discharge port of the coating liquid of the applicator and the coated surface of the coated member at the actual coating position, A gap measuring method and a gap measuring device capable of measuring even during coating are realized, and these gap measuring method and gap measuring device are adjusted so as to obtain an accurate gap based on a gap value measured during coating. An object of the present invention is to provide a coating apparatus and a coating method for obtaining a uniform and high-quality coating film without unevenness by coating.

  The object of the present invention is achieved by the means described below.

  (1) The gap measuring method of the present invention measures the gap between the discharge port surface including the discharge port of the coating liquid of the applicator and the coated surface of the coated member disposed relative to the discharge port. A method for measuring a gap, wherein a real image of an end portion of the discharge port surface and a reflection image of an end portion of the discharge port surface on a surface to be coated of a member to be coated are captured and the discharge port surface captured Based on the length between the real image at the end of the nozzle and the reflected image at the end of the discharge port surface, the gap between the discharge port surface of the cloth device and the coated surface of the coated member is calculated. It is characterized by that.

  (2) In the coating method of the present invention, the coating is performed while relatively moving at least one of the coated members held by the coating device and the holding unit in a direction parallel to the coated surface of the coated member. A coating method in which a coating liquid is discharged from a discharge port of a container to apply a coating liquid on a surface to be coated of a member to be coated, and before and / or during coating, The gap between the discharge port surface and the coated surface of the coated member is calculated, and the coating device is moved in a direction perpendicular to the coated surface of the coated member based on the obtained gap value. A gap between the discharge port surface of the container and the surface to be coated of the member to be coated is controlled.

  (3) The gap measuring device according to the present invention has a real image of the end of the discharge port surface including the discharge port of the coating liquid of the applicator, and on the coated surface of the coated member disposed relative to the discharge port. Based on the imaging unit that captures the reflection image of the end of the discharge port surface, and the length between the captured real image of the end of the discharge port surface and the reflection image of the end of the discharge port surface, And a gap calculating means for calculating a gap between the discharge port surface of the applicator and the application surface of the application member.

  (4) A coating apparatus according to the present invention includes a coating liquid supply means for supplying a coating liquid, an applicator having a discharge port for discharging the coating liquid supplied from the coating liquid supply means, a mounting table for holding a member to be coated, A height measuring means for measuring the height of the member to be coated held on the mounting table, the applicator, and at least one of the mounting table are relatively moved in a direction parallel to the coating surface of the coating member. And a gap measuring device.

    Furthermore, it is also preferable to have an applicator gap adjusting means for moving the applicator in a direction perpendicular to the application surface of the application member.

    According to the gap measuring method and the measuring apparatus of the present invention, a real image of the end portion of the discharge port surface of the applicator and a reflection image of the end portion of the discharge port surface reflected on the coated surface of the coated member are captured. Based on the length between the captured real image of the end of the discharge port surface and the reflected image of the end of the discharge port surface, the distance between the discharge port surface of the applicator and the coated surface of the coated member The gap between the discharge port surface and the surface to be coated can be accurately measured at the actual application position.

    In addition, the height of the applicator is adjusted so that the gap during coating is constant based on the accurately measured gap value using the above-described excellent gap measurement method and gap measurement device. Thus, a uniform coating film without unevenness can be easily obtained.

It is a schematic front view of the die coater 1 which is a coating device which has the gap | interval measuring means 4 of this invention. It is the perspective view which expanded and showed the imaging means 4a of FIG. 1, the slit die 2s, and its periphery. It is a perspective view which shows the condition where the real image of the slit die 2s and the reflected image on the board | substrate 9 are imaged by the imaging means 4a. It is a display figure in the monitor means 4c of the image | video imaged with the imaging means 4a in the state of FIG. FIG. 4 is a perspective view showing a state after the slit die 2s is raised by a predetermined amount E from the state of FIG. It is a display figure in the monitor means 4c of the image | video imaged with the imaging means 4a in the state of FIG. It is the perspective view which showed another example in which the gap | interval measuring means 4 was installed. It is the schematic front view which showed another example which installed the clearance measurement means 4. FIG.

    FIG. 1 is a schematic front view of a die coater 1 which is a coating apparatus having a gap measuring means 4 according to an embodiment of the present invention.

    As shown in FIG. 1, the die coater 1 includes a mounting table 11 that is a holding unit that holds and holds a substrate 9 that is a member to be coated by a suction unit (not shown), a coating unit 2 that includes a slit die 2s corresponding to a coating device, and a mounting table. 11 has a relative moving means 3 for moving the relative position 11 relative to the slit die 2s, a gap measuring means 4, a height distribution measuring means 5, a controller 7 and a coating liquid supplying means 8.

    Here, the relative moving means 3 includes a gantry 3a, a nut 3b, a ball screw 3c, a servo motor 3d, and a guide 3e. The mounting table 11 is guided by a guide 3e in a direction parallel to the surface to be coated of the member to be coated, in the horizontal direction in this apparatus, that is, in the X direction, and is screwed to the ball screw 3c via a nut 3b. The servo motor 3d can be driven to reciprocate between a position P0 and a position P2 indicated by a two-dot chain line. The reciprocation of the mounting table 11 is controlled by the controller 7.

    The coating liquid supply means 8 includes a coating liquid tank 8a, a coating liquid pump 8b that sends out the coating liquid in the coating liquid tank 8a, a pipe 8c that connects the coating liquid tank 8a and the coating liquid pump 8b, and a coating liquid. A pump 8b and a pipe 8d for connecting the coating means 2 are provided. The coating liquid tank 8a is preferably a sealed tank, and the inside is preferably pressurized to about 0.02 to 1 MPa by air or an inert gas (for example, nitrogen gas). Moreover, it is preferable that the coating liquid pump 8b is a syringe pump of the type which extrudes the liquid in the syringe 8f with the piston 8g as shown. When filling the coating liquid from the coating liquid tank 8a into the syringe 8f of the coating liquid pump 8b, the three-way valve 8e is opened so that the coating liquid tank 8a and the syringe 8f communicate with each other, and the piston 8g is moved downward. . When the coating liquid in the syringe 8f is sent to the slit die 2s, the three-way valve 8e is opened so that the slit die 2s and the syringe 8f communicate with each other, and the piston 8g is moved upward.

    The coating liquid pump 8b may be an intermittent constant capacity pump such as a diaphragm pump or the like, but may be fed by air pressure. The coating liquid pump 8b and the three-way valve 8e described above operate based on a signal from the controller 7.

    The applicator 2 is a column 2a attached to the gantry 3a of the relative moving unit 3, a guide 2b attached to the column 2a, a holder 2c guided by the guide 2b, and an applicator attached to the holder 2c. A slit die 2s. The slit die 2s connected to the pipe 8d of the coating liquid supply means 8 communicates with the slit 2h via a pipe 8d and a flow path (not shown), and discharges the coating liquid in the coating liquid tank 8a from the slit 2h. Can do. Here, the discharge port surface 2g including the slit 2h, which is a discharge port, becomes the lower surface of the slit die 2s and is disposed to face the coated surface 9a of the substrate 9. The coated surface 9a is the upper surface of the substrate 9, and is a surface to which the coating liquid discharged from the slit die 2s is applied.

    A ball screw 2f driven by a servo motor 2e is screwed to the holder 2c, and when the servo motor 2e is rotated forward and backward based on a signal from the controller 7, the holder 2c is guided by the guide 2b in the upper limit direction. The slit die 2s is moved up and down in the vertical direction, that is, in the Z direction. By raising and lowering the slit die 2s, the gap between the slit die 2s and the substrate 9 can be arbitrarily changed. The position of the slit die 2s in the Z direction is expressed using Z-axis coordinates indicated by a linear scale (not shown).

    A substrate height detector 5a constituting the height distribution measuring means 5 is attached to the support 2a via a substrate height detector mounting support 5b. The substrate height detector 5a is for measuring the height H of the substrate 9 with respect to the substrate suction holding surface 11a of the mounting table 11.

    The substrate height detector 5a is preferably a laser focus type laser length measuring device, but may be a triangular distance measuring type laser length measuring device or the like. The substrate height detector 5a measures the height H of the substrate 9 by irradiating the coated surface 9a of the substrate 9 on the mounting table 11 with laser light and receiving the reflected light from the coated surface 9a. is there. One substrate height detector 5a may be installed at the center in the width direction of the substrate, or one at each end in the width direction of the substrate.

    Next, the gap measuring means 4 includes an image pickup means 4a, a monitor means 4c for monitoring the picked-up gap state, a gap calculation means 4b for calculating a gap from the picked-up image on the monitor means 4c, and an image pickup means 4a. And an imaging means mounting column 4d for fixing the frame to the column 2a. The gap value calculated by the gap calculation means 4 b is transmitted to the controller 7. Further, an imaging command is transmitted from the controller 7 to the imaging means 4a, and a gap calculation command is transmitted to the gap calculation means 4b.

    Specifically, the imaging unit 4a includes an imaging element, a lens for imaging at a predetermined size, and illumination for imaging at a predetermined brightness.

    It is preferable to use a CCD (Charge Coupled Device) widely used for image processing as the imaging device.

    The size of a semiconductor element, which is one pixel of a CCD, is about several μm, and the pixels are arranged in units of several hundred to several thousand in length and breadth in a lattice shape.

    In addition, the lens generally has a principal ray called a telecentric optical system that is parallel to the optical axis of the lens, has no distortion at the center and periphery of the captured image, and is suitable for close-up imaging at high magnification. It is preferable to use a macro lens. This lens is also suitable for shape measurement because the size of the captured image does not change even if the distance from the lens to the object changes.

    Further, it is preferable to apply a metal halide lamp capable of adjusting the brightness to the illumination when taking an image, and attach this to the lens and the coaxial system.

    Next, a specific gap measuring principle and measuring method by the gap measuring means 4 will be described with reference to FIGS.

    FIG. 2 is an enlarged perspective view showing the imaging means 4a of FIG. 1, the slit die 2s, and the periphery thereof, and shows a situation in which the gap between the slit die 2s and the substrate 9 is measured. The imaging means 4a is preferably attached so as to image the gap from an angle so as not to contact the substrate 9.

    FIG. 3 is a perspective view showing a situation where a real image of the slit die 2s and a reflected image on the substrate 9 are being picked up by the image pickup means 4a.

FIG. 4 is a display diagram on the monitor means 4c of the video imaged by the imaging means 4a.
In the figure, the symbol with i at the end indicates a reflected image reflected on the coated surface 9a, and the symbol with d at the end indicates a dimension measured on the monitor means 4c.

    Referring to FIG. 3, when the gap between the ejection port surface 2g of the slit die 2s and the coated surface 9a of the substrate 9 is a gap value C, the optical axis L of the imaging means 4a is tilted from the coated surface 9a by an angle θ. The state is shown. At this time, the image pickup unit 4a picks up an end 2j of the discharge port surface 2g, which is a real image, and a reflected image 2ji on the coated surface 9a of the end 2j.

    Here, the reflected image 2ji directly picked up by the image pickup means 4a is such that the end 2j is reflected at the incident angle θ on the coated surface 9a. The end 2j and the reflected image 2ji imaged by the imaging means 4a in this way are displayed on the monitor means 4c as shown in FIG.

    At this time, the distance Dd, which is the distance between the end 2j and the reflected image 2ji of the end 2j on the monitor 4c, is equal to the actual distance D between the end 2j and the reflected image 2ji shown in FIG. It becomes equal to n · D obtained by multiplying the total enlargement magnification n by 4a and the monitor means 4c.

    In FIG. 3, the gap value C between the discharge port surface 2g and the coated surface 9a, which is the gap between the slit die 2s and the substrate 9, is C = 1 / Sinθ, and D = 1 / Cosφ = 1 / Cos (π / 2-2θ) = 2l · Sinθ · Cosθ is calculated as C = D / 2Cosθ. Here, l is the distance from the end 2j to the reflected image 2ji of the end 2j.

    As described above, when the distance Dd is measured and the angle θ is measured on the monitor unit 4c, the gap value C can be calculated from C = Dd / (2 · n · Cos θ).

    Next, a specific method for measuring the distance Dd and the angle θ will be described.

    First, for the distance Dd, the distance between the end 2j appearing on the monitor means 4c and the position of the reflection image 2ji of the end 2j is obtained by image processing by the gap calculating means 4b.

    There are several specific image processing methods. For example, if the positions of the edge 2j and the reflected image 2ji of the edge 2j are firmly determined by using the fact that the color and shade of the image change greatly, for example. The distance Dd that is the distance between the position of the end 2j and the position of the reflected image 2ji can be easily obtained.

    As for the angle θ, it is only necessary to measure the angle of the optical axis L of the image pickup means 4a attached to the die coater 1 shown in FIG. 2, but it is difficult to accurately measure the angle θ.

    Therefore, θ is indirectly obtained from the relationship of the gap value C = Dd / (2 · n · Cos θ). The specific method is demonstrated using FIG.3, FIG.4, FIG.5 and FIG.

    First, FIG. 5 shows a state when the slit die 2s is raised by a predetermined amount E from the state of FIG. In FIG. 5, the slit die 2 s and the reflection image 2 ji before rising are indicated by a one-dot chain line. Further, FIG. 6 shows the end 2j in the state of FIG. 5 and the reflected image 2ji of the end 2j taken by the image pickup means 4a and displayed on the monitor means 4c by a solid line. In FIG. 6, the positions of the end 2j of the discharge port surface 2g and the reflected image 2ji of the end 2j before the slit die 2s rises by E are indicated by a one-dot chain line. The end portion 2j and the reflected image 2ji indicated by the alternate long and short dash line are not actually displayed on the monitor means 4c, but the distance Dd between them is given to the gap calculating means 4b before the slit die 2s rises. It is remembered.

    On the other hand, in FIG. 5, the actual distance (shortest distance) between the end 2j after the slit die 2s is raised by a predetermined amount E and the reflected image 2ji of the end 2j is the reflection of the end 2j and the end 2j after the rise. The actual distance D1 between the images 2ji is indicated. As shown in FIG. 6, the distance D1 is D1d on the monitor means 4c, and D1d = n · D1.

    By the way, C = Dd / (2 · n · Cos θ) and C + E = D1d / (2 · n · Cos θ) in FIG. 5, and the movement amounts E1 of the end 2j before and after the ascent and the reflected image 2ji are E1 = E. Since the movement amount E1d of each of the end 2j and the reflected image 2ji on the monitor means 4c in FIG. 6 is represented by E1d = n · E1, it is obtained by E1d = (D1d−Dd) / 2. be able to. That is, when the slit die 2s is raised by a predetermined amount E, the distance D1d between the end 2j and the reflected image 2ji of the end 2j shown on the monitor means 4c and the distance Dd stored in the gap calculating means 4b are used. Thus, the angle θ is calculated from Cos θ = E1 / E = (D1d−Dd) / (2 · n · E).

    Since the angle θ is always a constant value after the imaging means 4a is once attached to the die coater 1, it is preferable to obtain it by the above method in a preparation step before measuring the actual gap.

    In this case, the gap value C = Dd / (2.multidot.Cos.theta.) = A.multidot.Dd and a = 1 / (2.multidot.Cos.theta.) = E / (D1d-Dd) to directly obtain .theta. Instead, it is convenient and preferable to obtain the conversion coefficient a.

    In the actual measurement of the gap value C, if the imaging means 4a is installed upstream of the slit die 2s in the application direction as shown in FIGS. 1 and 2, it is affected by the coating liquid discharged from the slit die 2s. In addition, the gap value C can always be measured even during application.

    The imaging means 4a may be fixed at one central position in the longitudinal direction of the slit die 2s as shown in FIG. 2, or the imaging means 4a is moved on the imaging means mounting column 4d in the longitudinal direction of the slit die 2s. You may make it measure the clearance gap of the arbitrary places of a longitudinal direction. Further, a plurality of imaging means 4a may be attached to the imaging means attaching column 4d in the longitudinal direction of the slit die 2s, and the gaps at arbitrary plural locations in the longitudinal direction of the slit die 2s may be measured simultaneously.

    When a plurality of image pickup means 4a are attached, it is preferable to arrange the two image pickup means 4a at both end positions in the longitudinal direction of the slit die 2s so that the gaps at both ends of the slit die 2s can be measured simultaneously. Further, a single imaging means 4a may be added to the central portion so that a total of three imaging means 4a may be provided so that a gap in the longitudinal center of the slit die 2s can be measured.

    FIGS. 7 and 8 are views showing an example in which the imaging means 4a is installed in another place. As shown schematically in FIG. 7, the gap value C may be measured by taking an image with the imaging means 4a from the longitudinal direction of the slit die 2s, or as shown schematically in FIG. The gap value C may be measured by the image pickup means 4a by refracting the optical axis using the mirror 4e at an arbitrary position in the direction.

    In the die coater 1 shown in FIG. 1, the mounting table 11 that holds the substrate 9 is moved in the X direction relative to the coating means 2 that does not move in the X direction. The application unit 2 may be moved relative to the table 11 in the X direction together with the imaging unit 4a to move both of them relative to each other. Further, both the mounting table 11 and the coating means 2 may be moved in the X direction.

    Now, with respect to the first coating method using the gap measuring device and the gap measuring method of the present invention described above, step 1: coating preparation step, step 2: gap measurement preparation step, step 3: substrate carry-in / gap confirmation step, step 4: Description will be made with reference to FIGS. 1 to 6 in the flow of coating / substrate unloading step.

Step 1: Application Preparation Step First, the coating liquid is passed from the coating liquid tank 8a to the slit die 2s at the origin position (the uppermost point) so that air is excluded. Subsequently, the syringe 8f and the coating liquid tank 8a are communicated with each other by the three-way valve 8e of the coating liquid pump 8b, and the piston 8g is moved to the lowest position to fill the syringe 8f with the coating liquid. Thereafter, the three-way valve 8e is switched so that the syringe 8f and the slit die 2s communicate with each other. As a result, when the piston 8g is started, the coating liquid can be discharged from the slit die 2s at any time, and the coating preparation process is completed.

Step 2: Gap Measurement Preparation Step In this step, a conversion coefficient a = E / (D1d−Dd) is obtained.

    First, the substrate 9 is loaded and sucked and held on the mounting table 11. Subsequently, until the gap measurement part of the substrate 9 comes directly below the substrate height detector 5a, the mounting table 11 is moved from the origin position (position P0) to be stationary, and the substrate height detector 5a sets the substrate height H. taking measurement. Then, using the measured substrate height H, the measurement preparation coordinate Zc of the slit die 2s is calculated from Zc = Z0 + H + Cc and stored in the controller 7.

    Here, Z0 is the Z direction of the slit die 2s when the substrate suction holding surface 11a and the discharge port surface 2g of the slit die 2s are in contact, that is, when the substrate suction holding surface 11a and the discharge port surface 2g are at the same height. This is a Z-axis coordinate representing the position of. Cc is a gap value set in the measurement preparation step, and is stored in the controller 7.

    Next, the mounting table 11 is moved to a position where the portion (gap measuring portion) where the height H of the substrate 9 has been measured is located immediately below the slit die 2s and stopped. Subsequently, in accordance with a command from the controller 7, the servo motor 2e is driven, and the slit die 2s is lowered from the highest point to the position of the calculated measurement preparation coordinate Zc to be stationary.

    In this state, the imaging unit 4a captures the end 2j of the discharge port surface 2g and the reflection image 2ji of the end 2j, and displays them on the monitor unit 4c as shown in FIG. The distance Dd, which is the distance from the end 2j to the reflected image 2ji of the end 2j, is obtained by image processing by the gap calculating means 4b and stored.

    Next, the slit die 2 s is raised by the height E in the Z direction in response to a command from the controller 7. After rising, the end 2j and the reflection image 2ji of the end 2j are picked up by the image pickup means 4a and displayed on the monitor means 4c as shown in FIG. 6, and the reflection image 2ji from the end 2j to the end 2j at that time is displayed. The distance D1d, which is a distance up to, is obtained by image processing by the gap calculation means 4b. Subsequently, the conversion coefficient a is calculated from a = E / (D1d−Dd), and stored in the gap calculation means 4b. Thus, the measurement preparation of the gap measuring means 4 is completed by obtaining the conversion coefficient a necessary for calculating the gap value C.

    After completion, the slit die 2s and the mounting table 11 are returned to the origin position and the substrate 9 is removed.

Step 3: Substrate Loading / Gap Confirmation Step In this step, after loading the substrate 9, it is confirmed whether the gap between the substrate 9 and the slit die 2s is within the allowable range, and if it exceeds the allowable value, it is corrected.

    First, in a state where the mounting table 11 is at the position P0 which is the origin position, the substrate 9 is mounted on the mounting table 11 by a substrate transport unit (not shown), and is sucked from the suction hole (not shown) to suck the substrate 9 to the mounting table 11. Hold. Subsequently, the mounting table 11 is moved until the coating start portion of the substrate 9 comes directly under the substrate height detector 5a, and after the stop, the substrate height H of the substrate 9 is measured by the substrate height detector 5a.

    Using the measured substrate height H, the coating height start coordinate Zs of the slit die 2s is calculated from Zs = Z0 + H + Cs and stored in the controller 7. Here, Cs is a set application gap value, which is input to the controller 7 and stored in advance.

    Next, after the mounting table 11 is moved to a position where the coating start portion of the substrate 9 is directly below the slit die 2s and stopped, the servo motor 2e is driven by the command from the controller 7 so that the slit die 2s is moved to the uppermost position. From the point, it is lowered to the position of the calculated application height start coordinate Zs to be stationary.

    At this time, the imaging unit 4a captures the end 2j of the discharge port surface 2g and the reflection image 2ji of the end 2j, displays them on the monitor unit 4c as shown in FIG. 4, and reflects from the end 2j to the end 2j. A distance Dd, which is the length to the image 2ji, is obtained by image processing by the gap calculating means 4b.

    The current gap value C is calculated from C = a · Dd using the distance Dd and the conversion coefficient a obtained in the measurement preparation step.

    If the difference between the obtained gap value C and the set application gap value Cs is equal to or smaller than the allowable value b, that is, | Cs−C | ≦ b, the process proceeds to the next application step. If | Cs−C |> b, the correction amount h is obtained from h = Cs−C, and the servo motor 2e is driven by the command from the controller 7 to raise and lower the slit die 2s by the correction amount h. At this time, if h is positive, the slit die 2s is raised, and if h is negative, it is lowered. Then, the current gap value C is measured again in the same manner as described above, and it is confirmed that | Cs−C | ≦ b. After the confirmation is completed, the corrected application height start coordinate Zs, that is, Zs = Z0 + H + Cs + h is stored in the controller 7, and then the process proceeds to the next application process.

Step 4: Application / Substrate Unloading Step The application start portion starts to move the substrate 9 immediately below the slit die 2s, and the coating liquid is supplied from the coating means 2 to the slit die 2s to start discharging onto the substrate 9. As a result, the coating liquid is applied onto the substrate 9.

    Specifically, while moving the mounting table 11 on which the substrate 9 is mounted toward the position P2 in FIG. 1 at a constant speed, the coating liquid pump 8b of the coating liquid supply means 8 is driven to remove the coating liquid from the slit die 2s. To supply. The supply flow rate of the coating liquid from the coating liquid pump 8b is determined according to a preset film thickness and coating speed.

    Here, during the application, the gap measuring means 4 always measures the gap between the discharge port surface 2g and the surface 9a to be applied, and the difference between the current gap value C and the set application gap value Cs is determined. If the allowable value is exceeded, an abnormal alarm may be issued to stop the application, and the outflow of defective products may be prevented.

    When the coating end portion of the substrate 9 reaches just below the discharge port surface 2g of the slit die 2s, the coating liquid pump 8b is stopped to stop the discharge of the coating liquid from the slit die 2s, and the slit die 2s is The application is finished by raising it to a predetermined position. The mounting table 11 continues to move even after the application is completed, and stops at the position P2.

    Then, the suction of the substrate 9 of the mounting table 11 stopped at the position P2 is released, and the substrate 9 is transported to the downstream process from the mounting table 11 by a substrate unloading means such as a robot (not shown). The slit die 2s moves to the uppermost point.

  In parallel with the unloading of the substrate 9, the three-way valve 8e and the piston 8g are operated to fill the syringe 8f with the coating liquid, and when completed, the valve 8e is switched to the side where the syringe 8f communicates with the slit die 2s.

    Thereafter, when coating is performed continuously, Step 3 and Step 4 are repeated.

    Next, a second coating method using the gap measuring method of the present invention will be described. In the second application method, even if the height of the substrate 9 changes at the application position, the slit die 2s is moved up and down in accordance with the change, and the application is performed while the gap between the substrate 9 is always kept constant. Make it.

    The second coating method is performed in exactly the same manner as the first coating method up to step 1: coating preparation step, step 2: gap measurement preparation step, and step 3: substrate carry-in / gap confirmation step.

    Step 4: In the coating / substrate unloading step, the coating liquid pump 8b of the coating liquid supply means 8 is driven while moving the mounting table 11 on which the substrate 9 is mounted toward the position P2 in FIG. The coating liquid flow rate based on the preset film thickness is supplied to the slit die 2s.

    And, while the substrate 9 is being moved, when the position Xsi (i = 1 to n) in the application direction with the application start portion on the substrate 9 as a base point passes directly under the substrate height detector 5a, The substrate height Hxi of the substrate 9 is measured. Further, for each measured substrate height Hxi, the coating height coordinate Zxi = Z0 + Hxi + Cs + h of the slit die 2s is calculated by the controller 7 and stored. When the position Xsi on the substrate 9 comes directly below the discharge port surface 2g of the slit die 2s, the slit die 2s is moved to the position of the coating height coordinate Zxi. In this way, even if the substrate height of the substrate 9 fluctuates every moment, the position of the slit die 2s can be adjusted by raising and lowering according to the fluctuation amount, so that the gap between the slit die 2s and the substrate 9 can be adjusted. Stable coating can be performed with the gap always kept at a constant gap value C.

    Here, during the application, as in the first application method, the gap between the discharge port surface 2g and the application surface 9a is measured by the gap measuring means 4, and the current gap value C is set. If the difference from the application gap value Cs exceeds the allowable value, an abnormality alarm may be issued and the application may be stopped to prevent the outflow of defective products.

    When the coating end portion of the substrate 9 reaches just below the discharge port surface 2g of the slit die 2s, the coating liquid pump 8b is stopped to stop the discharge of the coating liquid from the slit die 2s, and the slit die 2s is set to the origin. The application is terminated by raising the position (uppermost point). The mounting table 11 continues to move even after the application is completed, and stops at the position P2.

  And after carrying out the board | substrate 9 similarly to the 1st application | coating method, the mounting base 11 is returned to an origin position, and the coating liquid is filled with the syringe 8f, and a process is completed in preparation for subsequent application | coating.

    In both the first coating method and the second coating method, the measurement of the substrate height H is not performed by stopping the mounting table 11, but during the movement of the mounting table 11 from the position P 0 to the position P 2, It may be performed when the substrate height measurement position such as the coating start portion passes directly under the substrate height detector 5a.

    The gap measuring means 4 described above is an example incorporated in a die coater 1 that is applied to a sheet-to-be-coated member such as a glass substrate, but it is also applicable to regular gap measurement with a die coater that is applied to a continuous member to be coated. You can also.

    In addition, the applicator is not limited to a slit die, and even if the applicator is a nozzle that discharges coating liquid from a plurality of discharge holes arranged at a constant pitch, the gap between the nozzle and the member to be applied is determined by the gap measuring method of the present invention. It can also be measured.

    Furthermore, the member to be coated is not limited to glass, and any member can be used as long as it can capture a reflected image of the discharge port.

    Further, as shown in FIG. 3, since the distance from the end 2j of the discharge port surface 2g to the imaging unit 4a is different from the distance from the reflected image 2ji of the end 2j to the imaging unit 4a, for example, the end 2j When the end portion 2j and the reflection image 2ji of the end portion 2j are simultaneously imaged in a focused state, the reflection image 2ji may be imaged in a blurred state depending on the performance of the lens. In such a case, after imaging the end 2j in a state where the end 2j is focused, the position of the imaging means 4a is moved so that the reflected image 2ji is in focus, and then the reflected image 2ji is captured. To do. Then, the distance calculation unit 4b may obtain the distance Dd from the end 2j to the reflected image 2ji by combining the two images on the monitor unit 4c.

    Further, in order to clearly capture the position of the end 2j of the discharge port surface 2g and the reflected image 2ji of the end 2j with the imaging means 4a, the end 2j is a linear edge and R = 0.5 mm or less. Is preferred.

    FIG. 1 shows an example in which the imaging means 4a is attached so as to image in the application direction on the upstream side of application, but it may be attached only on the downstream side of application or on both the upstream and downstream sides of application. If there are imaging means 4a on the upstream and downstream sides of the coating, the gap values C1 / C2 on the upstream side / downstream side of the discharge port surface 2g can be measured, and the average gap value or the smaller one can be measured. It is possible to control the gap value as a reference.

    Further, the image pickup means 4a is moved as shown in FIG. 2 from the one end to the opposite end in the longitudinal direction of the slit die 2s, that is, in the direction orthogonal to the coating, and continuously has a gap value C. And the distribution of the gap value C in the longitudinal direction may be obtained.

Example 1
The gap set by the die coater 1 was measured by the gap measuring means 4.

  In the die coater 1 shown in FIG. 1, the mounting table 11 has a suction surface with a width (substrate width direction) of 600 mm and a length (application direction) of 1000 mm, and the substrate 9 has a width (substrate width direction) of 570 mm. A transparent soda glass substrate having a length (application direction) of 970 mm and a thickness of 2 mm is used, and the slit die 2s of the application means 2 has a length in the substrate width direction (discharge width) of the slit 2h which is a discharge port for the coating liquid. ) A width of 550 mm and a width in the coating direction (slit gap) of 300 μm were used.

    The imaging means 4a is a combination of a 5 million pixel type CCD in which 2448 pixels of 3 μm square size are arranged in the horizontal direction and 2044 in the vertical direction, and a telecentric macro lens with coaxial illumination and a magnification of 6 times. did.

    The imaging means 4a has a horizontal field of view of 1.224 mm, a vertical field of view of 1.022 mm, a horizontal imaging resolution of 0.5 μm, and a vertical imaging resolution of 0.5 μm. One was placed in the center of the substrate width direction (longitudinal direction of the slit die 2s).

    In this die coater 1, the substrate 9 was placed on the mounting table 11 by an external substrate transfer robot, and held by suction.

    Next, the mounting table 11 was moved by the moving means 3 and stopped so that the portion 3 mm inside from the substrate end on the moving head side was directly below the substrate height detector 5a. In this state, the height H of the substrate 9 was measured by the substrate height detector 5a to obtain H = 2000 μm, and the value was stored in the controller 7.

    Next, the mounting table 11 was moved to a position where a portion 3 mm inside from the end of the substrate was directly below the discharge port surface 2g of the slit die 2s. When the measurement preparation gap value Cc = 200 μm, the discharge port surface 2g and the substrate suction holding surface 11a have the same height, the coordinate Z0 is Z0 = 0 μm, the height H of the substrate 9 is 2000 μm, and Zc = Z0 + H + Cc. The slit die 2s was lowered to a position of 2200 μm.

    Next, in this state, the gap imaging unit 4a images the positions of the end 2j and the reflection image 2ji of the end 2j, and the distance Dd from the end 2j to the reflection image 2ji of the end 2j on the monitor unit 4c. Was obtained by the gap measuring means 4, and as a result, 397.5 μm was calculated for Dd.

    Next, after raising the slit die 2s by E = 10 μm, the gap imaging means 4a again images the positions of the end 2j of the discharge port surface 2g and the reflected image 2ji of the end 2j, and on the monitor means 4c. As a result of obtaining the distance D1d from the end 2j to the reflected image 2ji of the end 2j by the gap measuring means 4, it was calculated to be 417.0 μm. From the above, the conversion coefficient a = E / (D1d−Dd) = 0.513 was calculated. The gap value C before being increased by 10 μm from C = a · Dd was calculated to be 203.8 μm and displayed on the monitor means 4c. With respect to the measurement preparation gap value Cc = 200 μm, which was the set gap value, the measured gap value was 203.9 μm, and it was confirmed by the gap measurement means 4 that the gap could be set with an accuracy within 4 μm.

    Furthermore, when the 200 μm and 205 μm block gauges were used to measure the set 200 μm gap, the 200 μm block gauge could be inserted into the gap, but the 205 μm block gauge could not be inserted into the gap. From this, it was verified that the gap could be set with an accuracy of 5 μm or less by another means.

(Example 2)
With the die coater 1 equipped with the gap measuring method and the gap measuring apparatus of the present invention, a partition wall forming paste as a plasma display member was applied to a glass substrate while controlling the gap to be always constant.

    First, using the same substrate 9 and die coater 1 as in Example 1, preparation for gap measurement for obtaining the conversion coefficient a was performed in the same manner as in Example 1 to obtain conversion coefficient a = 0.513.

    Next, the substrate 9 cleaned for coating was sucked and held on the mounting table 11 at the position P0.

    Subsequently, the substrate 9 is moved toward the position P2 until the coating start portion located at a position 5 mm from the edge of the substrate 9 is directly below the slit die 2s, and the coating start portion is moved to the height of the substrate during this movement. The substrate height Hx1 = 1998 μm was obtained when passing directly under the detector 5a. Then, from the value of the substrate height Hx1 and the set coating gap value Cs = 250 μm, the coating height start coordinate Zs = 2248 μm was obtained, and the slit die 2s was lowered to that position. At this time, when the gap was measured by the gap measuring means 4, the actual gap value C was 264 μm. As a result, a correction value h = Cs−C = −14 μm was obtained.

    Then, after the slit die 2s was moved to the position where the coating height start coordinate Zs = 2248 + h = 2248-14 = 2234 μm and the current gap value C was measured, it was 250 μm. Since the effectiveness of the correction could be confirmed with this, the controller 7 stores the coating height start coordinate Zs = Z0 + Hx1 + Cs + h h = −14.

    Subsequently, the stationary substrate 9 is started to move toward the position P2, and a partition wall forming paste having a viscosity of 20 Pa · sec and a solid content concentration of 40% is discharged from the slit die 2s to obtain a coating thickness of 300 μm, Coating was started on the substrate 9 at a coating speed of 3 m / min.

    Then, during the movement of the substrate 9, the substrate height Hxi was measured for each position of 10 mm pitch from the coating start portion when the substrate 9 passed directly under the height detector 5 a. As a result, the substrate height Hxi changed between 1996 μm and 2013 μm, and the coating height coordinate Zxi = Hxi + 250-14 was calculated and stored in the controller 7 each time. When the location where the substrate height Hxi of the substrate 9 was measured came directly under the slit die 2s, the slit die 2s was moved to the calculated coating height coordinate Zxi. In addition, the gap value C was measured by the gap measuring means 4 during coating, and the difference from the set coating gap value Cs was monitored. When | Cs−C | ≧ 5 μm, the abnormal stop was performed. Cs-C | was always less than 5 μm.

    The substrate on which the coating was completed was carried out to a subsequent process, and then dried at 100 ° C. for 20 minutes in a drying furnace using a radiation heater. In the same manner as described above, the same coating was performed on 50 substrates, and the partition wall coating film thickness distribution after drying was measured in the coating direction over the entire surface of the substrate. As a result, all 50 substrates were within the allowable range of 120 μm ± 3 μm.

(Comparative example)
Coating was performed on 50 substrates with the die coater 1 in exactly the same manner as in Example 2 except that the measurement of the gap value using the gap measuring means 4 of the present invention and the correction associated therewith were not performed. As a result, coating failure occurred successively, such as the coating film being interrupted, and normal coating could not be performed.

  The present invention is based on a gap measuring method and a gap measuring device between a coating device and a member to be coated, such as a die coater that coats the gap between the coating device and a member to be coated with high accuracy, and a result of the gap measurement. It can be suitably used for a coating method and a coating apparatus.

1: Die coater 2: Application means 2a: Support column 2b: Guide 2c: Holder 2e: Servo motor 2f: Ball screw 2g: Discharge port surface 2gi: Reflected image on discharge port surface 2g 2h: Slit 2j: End of discharge port surface 2g Portion 2ji: Reflected image of end 2j of discharge port surface 2g 2s: Slit die 3: Relative moving means 3a: Mount 3b: Nut 3c: Ball screw 3d: Servo motor 3e: Guide 4: Gap measuring means 4a: Imaging means 4b : Gap calculation means 4c: Monitor means 4d: Imaging means mounting column 4e: Mirror 5: Height distribution measuring unit 5a: Substrate height detector 5b: Substrate height detector mounting column 7: Controller 8: Coating liquid supply unit 8a : Coating liquid tank 8b: Coating liquid pump 8c: Piping 8d: Piping 8e: 3-way valve 8f: Syringe 8g: Piston 9: Substrate 9a: Surface to be coated 11 Mounting table 11a: Substrate suction holding surface H: Height of substrate 9 P0, P2: Position of mounting table 11 C: Gap value Cc: Measurement preparation gap value Cs: Set application gap value D: Between end 2j and end 2j The actual distance between the reflected images 2ji D1: The actual distance between the raised edge 2j and the reflected image 2ji of the edge 2j Dd: The reflected image of the edge 2j and the edge 2j of the discharge port surface 2g on the monitor means 4c 2j distance D1d: distance between the end 2j of the ejection port surface 2g on the monitor means 4c after ascending and the reflected image 2ji of the end 2j L: optical axis E: ascending amount E1: end 2j before and after ascending E1d: The amount of movement of the end 2j on the monitor means 4c before and after the ascent and the amount of movement of the reflected image 2ji n: Total magnification of the imaging means 4a and the monitor means 4c Zc: Measurement preparation coordinates Zs: Application height start coordinate Zxi: Application height coordinate

Claims (5)

  A gap measuring method for measuring a gap between a discharge port surface including a discharge port of a coating liquid of an applicator and a coated surface of a coated member disposed relative to the discharge port, the discharge port The real image of the edge part of the surface and the reflection image of the edge part of the discharge port surface on the coated surface of the member to be coated are imaged, and the real image of the edge part of the imaged discharge port surface and the discharge port surface A gap measuring method, comprising: calculating a gap between a discharge port surface of the applicator and a surface to be coated of the member to be coated based on a length between reflection images at the end of the coating member.   The coating liquid is discharged from the discharge port of the applicator while relatively moving at least one of the coated members held by the coating device and the holding means in a direction parallel to the coated surface of the coated member. A coating method in which a coating liquid is applied to a surface to be coated of a member to be coated, and before and / or during coating, using the gap measuring method according to claim 1, The gap between the coated member and the coated surface is calculated, and the applicator is moved in a direction perpendicular to the coated surface of the coated member based on the obtained gap value to discharge the discharge port surface of the coated device. And a coating surface of the coated member to be controlled.   A real image of the end portion of the discharge port surface including the discharge port of the coating liquid of the applicator, and a reflection image of the end portion of the discharge port surface on the coated surface of the coated member disposed relative to the discharge port; Based on the length between the imaged image pickup means for picking up the image and the captured real image of the end of the discharge port surface and the reflected image of the end of the discharge port surface, the discharge port surface of the applicator and the coating target And a gap calculating unit that calculates a gap between the member and the surface to be coated. Coating liquid supply means for supplying the coating liquid;
An applicator having a discharge port for discharging the coating liquid supplied from the coating liquid supply means;
A mounting table for holding a member to be coated;
Height measuring means for measuring the height of the member to be coated held on the mounting table,
Moving means for relatively moving at least one of the applicator and the mounting table in a direction parallel to a surface to be coated of the member to be coated;
A coating apparatus comprising the gap measuring device according to claim 3. 5. The coating apparatus according to claim 4, further comprising an applicator gap adjusting unit that moves the applicator in a direction perpendicular to a surface to be coated of the member to be coated.

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