JP2017056367A - Coating device and coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of surely detecting an end part position of a coating film, even if the coating film is an undried state.SOLUTION: A coating device is provided with an imaging part 91 for imaging an end part Rf of a coating film F formed on a surface of a base material S and an illumination part 93 for illuminating an imaging area Ri. The illumination part 93 emits the light L2, L3 and L4 in the direction having a component in the direction toward the end part from a central part of the coating film F in the width direction Dw of the base material S. The imaging part 91 is arranged between an optical path of the illumination light incident on the imaging area Ri and an optical path of the regular reflection light L2 and L3 emitted from the imaging area Ri. Since the regular reflection light L4 reflected by a curved surface part of the end part Rf of the coating film F is emitted at a larger angle than an incidence angle, the occurrence of halation when being made incident on the imaging part 91 can be prevented.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a coating apparatus and a coating method for forming a coating film on a surface thereof while conveying a sheet-like substrate, and particularly to a technique for detecting an end position of the coating film.

  In the technique of forming a substantially flat coating film by applying a coating liquid on the surface of a sheet-like substrate while conveying it, it is possible to detect the end position in the width direction orthogonal to the conveyance direction of the substrate. May be necessary. For example, in the technique described in Patent Document 1, a coating liquid is discharged from a slit nozzle disposed in proximity to the surface of a long sheet-like base material that is conveyed by a roll-to-roll method, and a coating film is formed on the surface of the base material. (Coating film) is formed.

  In this technology, in order to align the position of the coating film formed on both surfaces of the substrate, the coating film is detected by detecting the difference in height between the formed coating film and the substrate surface with a two-dimensional laser displacement meter. Is determined. More specifically, a two-dimensional laser displacement meter in which a plurality of distance measuring units that measure the distance to the object by irradiating the object with laser light and detecting its reflection is opposed to the surface of the substrate. The position where the output signal of the distance measuring unit changes rapidly is the end position of the coating film.

Japanese Patent Laying-Open No. 2012-212619 (for example, FIGS. 3 and 4)

  For example, for the purpose of managing the amount of substance (also referred to as a basis weight) supplied as a coating film to the substrate surface, there is a case where more accurate detection of the end position is required. In order to make this possible, it is conceivable that the end of the coating film is imaged by a high-resolution imaging device such as a CCD camera and the end position is detected by image analysis. In particular, for the purpose of real-time control such as changing the supply amount of the coating liquid based on the position detection result, it is necessary to detect the position when the coating liquid is in an undried state. Consideration is required. However, at present, no technology that can meet such needs has been established.

  The present invention has been made in view of the above problems, and in a coating apparatus and a coating method for forming a coating film on a surface thereof while conveying a sheet-like base material, the coating film is in an undried state. Even so, an object of the present invention is to provide a technique capable of reliably detecting the end position of the coating film.

  In one aspect of the coating apparatus according to the present invention, in order to achieve the above-described object, a coating unit that transports a sheet-like base material, and a coating liquid is continuously applied to the surface of the base material to be transported. A coating means for forming a substantially flat coating film, and a width that is arranged toward the surface of the base material and is parallel to the surface of the base material and orthogonal to the transport direction of the base material among the surfaces of the base material Based on an image pick-up means for picking up an image in an image pickup area including an end of the coating film in a direction, an illuminating means for irradiating illumination light toward the image pick-up area, and an image picked up by the image pickup means, the width direction A position detection unit that detects a position of the end of the imaging unit, and an incident direction of the illumination light to the imaging region is parallel to a normal direction of the imaging region and a direction component from the imaging unit toward the imaging region And a central portion of the coating film parallel to the width direction A direction component toward the end, and the imaging means is between the optical path of the illumination light incident on the imaging area and the optical path of the regular reflection light of the illumination light from the imaging area The light from the imaging area is received at the position.

  Moreover, in one aspect of the coating method according to the present invention, in order to achieve the above-described object, the coating unit applies the coating liquid to the surface of the substrate to be conveyed while conveying the sheet-like substrate by the conveying unit. A coating step of continuously coating to form a substantially flat coating film, and the coating in a width direction parallel to the surface of the base material and orthogonal to the transport direction of the base material among the surfaces of the base material Based on the imaging step of imaging the imaging area by the imaging means while illuminating light enters the imaging area including the edge of the film, and the edge in the width direction based on the image captured by the imaging means A position detection step of detecting a position of a part, and the incident direction of the illumination light to the imaging region is parallel to a normal direction of the imaging region and a direction component from the imaging means toward the imaging region, and Parallel to the width direction, the coating film A direction component having a direction component from a central portion toward the end portion, and the imaging unit includes an optical path of the illumination light incident on the imaging region, and an optical path of regular reflection light of the illumination light from the imaging region. The light from the imaging region is received at a position between.

  When the coating liquid applied to the substrate surface is in an undried state, the coating film contains a liquid component, and the surface generally has a relatively high reflectance with respect to illumination light. Moreover, the edge part of the coating film is a curved surface by the influence of the surface tension of a liquid, and the wettability with respect to a base material. Due to these reasons, an image suitable for detecting the edge position with high accuracy is obtained by direct incidence of strong reflected light, which is generated when the illumination light is reflected on the surface of the coating film, to the imaging means. There may not be. For example, the end position may not be able to be determined due to halation of the coating film caused by specular reflection light and loss of image information.

  In view of this, in the invention configured as described above, when an imaging area including the edge of the coating film in the width direction on the surface of the base material is imaged by the imaging means, the illumination means enters the imaging area. The direction of illumination light having a direction component parallel to the normal direction of the imaging region and extending from the imaging means to the imaging region and a direction component parallel to the width direction and extending from the center to the end of the coating film is defined as the incident direction. To do. The imaging means receives light from the imaging region at a position between the optical path of the illumination light incident on the imaging region and the optical path of the regular reflection light of the illumination light from the imaging region.

  In such a configuration, when the coating film is not formed on the substrate surface, the regular reflection light of the illumination light incident on the substrate surface in the imaging region is emitted from the imaging region at the same reflection angle as the incident angle. Is done. Since the imaging means is provided outside the optical path of the regular reflection light, the regular reflection light from the substrate surface does not enter the imaging means. Further, when the coating film is formed on the substrate surface, the regular reflection light from the substantially flat surface portion of the coating film has the same reflection angle as the incident angle as the regular reflection light from the substrate surface. Since it is emitted, it does not enter the imaging means.

  On the other hand, since the incident angle on the coating film surface is different from the incident angle on the substrate surface at the curved surface portion of the coating film end, the specularly reflected light is not necessarily emitted at the same reflection angle as the incident angle on the substrate surface. . However, the surface of the coating film in this part has a component in the direction from the center to the end of the coating film in the width direction, so that the regular reflection light viewed from the substrate surface The exit angle is larger than the incident angle. That is, the regular reflection light at this time is emitted in a direction further away from the imaging means than the optical path of the regular reflection light on the substrate surface. Therefore, also in this case, the specularly reflected light does not enter the imaging means.

  In this way, illumination light having a direction component parallel to the width direction and having a direction component from the center to the end of the coating film is incident on the imaging region, and the optical path of the incident light and regular reflection from the substrate surface By allowing the imaging unit to receive light from the imaging region and perform imaging between the optical path of the light, it is avoided that specularly reflected light is directly incident on the imaging unit that images the edge of the coating film. Factors that hinder the detection of the end position, such as halation, can be eliminated.

  As described above, according to the present invention, when the imaging region including the edge of the coating film in the width direction is imaged by the imaging unit on the surface of the sheet-like substrate, the incident direction of the illumination light is changed in the width direction. Between the optical path of the illumination light incident on the imaging region and the optical path of the regular reflection light of the illumination light from the imaging region. The imaging means performs imaging at the position. Therefore, the specularly reflected light from the coating film is prevented from entering the imaging means, and even if the coating film is undried and has a high reflectance, the end position of the coating film is It can be detected reliably.

It is a figure which shows schematic structure of one Embodiment of the coating device concerning this invention. It is a figure which shows the structure of an imaging unit. It is a figure which shows the direction of the illumination light in this embodiment. It is a figure which shows the optical path of the regular reflection light when the coating film is formed in the base-material surface. It is a figure which shows the matter which should be considered in imaging. It is a flowchart which shows the outline | summary of the coating process in this embodiment. It is a figure which shows the modification of an illumination part. It is a figure which shows the modification of an imaging part. It is a figure which shows the case which forms and forms a some coating film in a base material. It is a figure which shows the other example in the case of arrange | positioning a some imaging unit.

  FIG. 1 is a diagram showing a schematic configuration of an embodiment of a coating apparatus according to the present invention. This coating apparatus 100 is an apparatus for applying a paste-like coating liquid to a sheet-like substrate S conveyed by a roll-to-roll method. For example, a battery electrode such as a lithium ion secondary battery is used. It can be used for manufacturing. In order to uniformly indicate directions in the following drawings, an XYZ orthogonal coordinate system is set as shown in FIG. Here, the XY plane is a horizontal plane, and the Z axis represents a vertical axis. More specifically, the (−Z) direction represents a vertically downward direction.

  The coating apparatus 100 includes a tank 1 that stores therein a coating liquid to be applied, and a nozzle 5 that discharges the coating liquid supplied from the tank 1. By a liquid feeding system 2 provided between the tank 1 and the nozzle 5, the coating liquid in the tank 1 is sent out toward the nozzle 5 and discharged from a slit-like discharge port provided at the tip of the nozzle 5. . The coating apparatus 100 includes a control unit 3 that controls the operation of the entire apparatus.

  The liquid feeding system 2 includes a pipe 21 that connects between the tank 1 and the nozzle 5, and a pump 22 that is inserted in the pipe 21 and causes the coating liquid to flow through the pipe 21. It is desirable for the pump 22 to be capable of delivering a highly viscous coating liquid at a stable flow rate. As such a pump, for example, a screw pump can be used, and for example, a MONO pump which is a kind of single screw pump can be suitably applied. The operation of the pump 22 is controlled by the control unit 3, and the control unit 3 controls the pump 22 to adjust the flow rate of the coating liquid in the liquid feeding system 2.

  A substrate S to which the coating liquid is applied is disposed by the transport unit 7 at a position facing the discharge port of the nozzle 5. Specifically, the long sheet-like base material S wound in a roll shape is set on the supply roller 71 of the transport unit 7, and one end portion of the base material S drawn from the roll is a take-up roller 74. It is wound around. When the take-up roller 74 rotates in the direction of the arrow Dr in the figure, the substrate S is unwound from the supply roller 71, conveyed in the direction of the arrow Ds, and taken up by the take-up roller 74. In this way, a tension roller 72 and a backup roller 73 are provided on the transport path of the base material S spanned between the supply roller 71 and the take-up roller 74. That is, the base material S drawn from the supply roller 71 is wound around the surfaces of the tension roller 72 and the backup roller 73, and the base material S that has passed through the surface of the backup roller 73 is taken up by the take-up roller 74.

  The tension roller 72 applies a certain tension to the base material S that is transported along the transport path. Thereby, the slack of the base material S in the transport path is prevented, and the base material S is transported in a stable posture. That is, the base material S is transported while maintaining a substantially flat posture between the rollers arranged in the transport path. In the example of FIG. 1, the base material S is in a substantially horizontal posture between the backup roller 73 and the take-up roller 74. The conveyance direction Ds of the base material S at this time is the (+ Y) direction.

  That is, the transport unit 7 has a function as a means for holding the base material S that is an application target and a function as a means for transporting the same. The transport unit 7 further includes a roller driving mechanism 75 that rotates the winding roller 74 at a predetermined rotational speed in accordance with a control command from the control unit 3. The supply roller 71, the tension roller 72, and the backup roller 73 are driven rollers having no drive mechanism.

  As described above, the nozzle 5 is arranged so that one of the main surfaces of the base material S supported and transported by the transport unit 7 faces the other surface of the portion in contact with the backup roller 73. In other words, the base material S is opposed to the nozzle 5 by the base material S being wound around the surface of the backup roller 73 disposed so as to face the nozzle 5. The coating liquid discharged from the nozzle 5 is applied to the surface of the substrate S. By transporting the substrate S in the direction of the arrow Ds, the coating liquid can be applied to the substrate S while the nozzle 5 is scanned and moved relative to the substrate S. By applying the coating liquid with the nozzle 5 facing the region of the surface of the substrate S where the back surface is in contact with the backup roller 73, the coating is performed while maintaining a stable gap between the nozzle 5 and the surface of the substrate S. It can be performed.

  The nozzle 5 extends on a surface facing the surface of the base material S wound around the backup roller 73 along a width direction of the base material S, that is, a direction orthogonal to the longitudinal direction of the base material S (conveying direction Ds). It has a slit-shaped opening. By continuously discharging a coating solution in a fixed amount from the opening, a substantially flat coating film is formed on the surface of the substrate S by the coating solution.

Here, for example, an active material layer is laminated on the surface of the current collector layer by using a conductive sheet such as a metal functioning as a current collector as the substrate S and using a paste containing an active material as a coating liquid. It is possible to manufacture a battery electrode. Such a coating liquid generally has a relatively high viscosity. For example, a coating liquid having a viscosity of about 50 Pa · s to 300 Pa · s at a shear rate of 10 s ⁻¹ can be used. Moreover, as the base material S, for example, a metal thin film formed on the surface of a resin sheet may be used.

  Further, the curing unit 8 is provided at a position downstream of the backup roller 73 and upstream of the take-up roller 74 in the transport direction of the substrate S by the transport unit 7. The curing unit 8 promotes the volatilization of the solvent component of the coating solution by supplying, for example, dry air, hot air, infrared rays, etc. to the coating solution applied to the substrate S that is passed through the curing unit 8. Dry and cure. When the coating liquid contains a material that cures in response to a specific electromagnetic wave, the coating liquid may be configured to irradiate the coating liquid. The length of the curing unit 8 along the conveyance path of the substrate S corresponds to the curing time of the coating liquid.

  In addition, the imaging unit 9 is provided at a position downstream of the backup roller 73 and upstream of the curing unit 8 in the transport direction of the substrate S by the transport unit 7. The imaging unit 9 is provided for detecting the end position of the coating film formed by the coating liquid applied to the surface of the substrate S.

  FIG. 2 is a diagram illustrating the configuration of the imaging unit. More specifically, FIG. 2A is an external perspective view showing the configuration of the imaging unit 9, and FIG. 2B is a side view showing the configuration of the imaging unit 9. As shown in FIG. 2A, the nozzle 5 is disposed opposite the substrate S wound around the backup roller 73 with the width direction Dw of the substrate S as the longitudinal direction. In other words, the nozzle 5 is disposed close to the surface of the backup roller 73 with the axial direction of the backup roller 73 as the longitudinal direction. In this example, the width direction Dw of the base material S and the axial direction of the backup roller 73 are parallel to each other and equal to the X direction.

  With such a configuration, a coating film F having a substantially constant thickness is formed on the entire surface of the base material S except for both ends in the width direction Dw. The imaging unit 9 is disposed in the vicinity of the end in the width direction Dw of the undried coating film F immediately after coating. The imaging unit 9 includes a right unit 9a disposed near the right end Rf of the coating film F when viewed along the transport direction Ds of the substrate S, and a left unit 9b disposed near the left end Lf. Is provided.

  The right unit 9a includes an imaging unit 91 that captures an image of the end Rf including a part of the right end Rf of the coating film F in a substantially rectangular imaging region Ri, and an illumination unit 93 that illuminates the imaging region Ri. I have. The imaging unit 91 is a camera that incorporates an imaging element such as a CCD or a CMOS sensor, and periodically images the imaging region Ri at a predetermined time interval. Specifically, an area including the peripheral area centered on a part of the surface of the substrate S on which the right end Rf is estimated to be located when the coating film F is properly formed is an imaging area Ri. The imaging unit 91 is positioned so that Therefore, the obtained image includes both the surface of the substrate S and the coating film F, and a boundary line between them appears across the image.

  Image data obtained by imaging is sent to the control unit 3. The control unit 3 detects the position of the right end Rf of the coating film F in the image by analyzing the image data. For example, the end position can be detected based on the difference in image density between the coating film F and the substrate S.

  The illumination unit 93 is provided near the imaging unit 91 at a position closer to the center side of the base material S and the coating film F than the imaging unit 91 in the width direction Dw, and the transport direction Ds of the base material S is long. It has a bar-shaped illumination light source.

  Similarly, the left unit 9b includes an imaging unit 92 that captures a part of the left end portion Lf of the coating film F in the substantially rectangular imaging region Li, and an illumination unit that illuminates the imaging region Li. 94. The configuration of the imaging unit 92 is the same as that of the imaging unit 91 of the right unit 9a. Image data obtained by imaging is sent to the control unit 3, and the position of the left end Lf of the coating film F in the image is detected from the image data. By detecting the positions of both ends Rf and Lf, the coating width, that is, the length of the coating film F in the width direction Dw is obtained.

  Since the width of the coating film F changes depending on the amount of the coating liquid supplied from the nozzle 5, the width of the coating film F is obtained, and the supply amount of the coating liquid is controlled according to the result to obtain a desired value. A coating film F having a width can be formed. Further, the supply amount (weight per unit area) of the constituent material of the coating film F to the surface of the substrate S can be adjusted. Specifically, the control unit 3 detects the positions of both end portions Rf and Lf from the images captured by the imaging units 91 and 93, and sets the width of the coating film F obtained from the detection result to a predetermined target. Compared with the value, the delivery amount of the coating liquid from the pump 22 is increased or decreased so that the difference becomes smaller.

  For this purpose, it is necessary to measure the width of the coating film F immediately after the coating liquid is applied to the substrate S. Therefore, the imaging of the ends Rf and Lf is performed in a state where the coating film F is not dried at a position as close as possible to the nozzle 5 at a position downstream of the nozzle 5 in the transport direction Ds. Further, in order to enable stable imaging, imaging is performed at a portion where the base material S wound around the backup roller 73 becomes flat away from the backup roller 73. For the same purpose, the base material S is used. May be configured to take an image at a portion wound around the backup roller 73.

  As shown in FIG. 2B, the illumination units 93 and 94 illuminate the imaging regions Ri and Li from an oblique direction, respectively. More specifically, the illumination unit 93 is arranged such that the light exit surface 931 is tilted directly below, that is, from the (−Z) direction to the (+ X) direction. On the other hand, the illumination unit 94 is arranged such that the light exit surface 941 is inclined from the (−Z) direction to the (−X) direction. The broken lines indicate the emission ranges of the illumination light from the light exit surfaces 931 and 941, and as can be seen, the illumination light emitted from the illumination unit 93 and incident on the imaging region Ri has a (−Z) direction component and (+ X ) Direction component. Further, the illumination light emitted from the illumination unit 94 and incident on the imaging region Li has a (−Z) direction component and a (−X) direction component. Furthermore, a component in the (−Y) direction or the (+ Y) direction may be included.

  As described above, the illumination light emitted from the illumination units 93 and 94 has a downward direction component from the illumination units 93 and 94 toward the surface of the base material S in the vertical direction. Further, in the horizontal direction, there is an outward direction component from the center portion to the end portion of the coating film F in the width direction Dw of the substrate S. More specifically, the direction of the illumination light emitted from the illumination unit 93 is a direction component from the central portion of the coating film F toward the right end Ri in the width direction Dw, and illumination emitted from the illumination unit 94. The light direction has a directional component from the central portion of the coating film F toward the left end Li in the width direction Dw.

  The reason why the illumination unit is configured as described above will be described next. Hereinafter, the operation of the imaging unit 9 will be described by taking the right unit 9a as an example, but the principle is the same for the left unit 9b.

  FIG. 3 is a diagram showing the direction of illumination light in this embodiment. As illustrated in FIG. 3A, the imaging unit 91 is disposed to be opposed to the surface of the substrate S so that the imaging optical axis indicated by the alternate long and short dash line is perpendicular to the surface of the substrate S. A dotted line indicates an imaging range of the imaging unit 91. An area included in the imaging range of the imaging unit 91 on the surface of the base material S is the imaging area Ri.

  Illumination light emitted from the illumination unit 93 arranged on the (−X) side of the imaging region Ri is incident on the imaging region Ri from an oblique direction. Illumination light L1 having a component in the (+ X) direction with respect to the imaging region Ri and incident at an incident angle θ is specularly reflected on the surface of the substrate S and is emitted at an emission angle θ. A broken line and a hatched region sandwiched between the broken lines indicate a spread range of light that is incident on the imaging region Ri from the illumination unit 93 and is regularly reflected, and the illumination unit 93 is (−X) with respect to the surface of the substrate S. The specularly reflected light incident obliquely downward from the side is emitted obliquely upward to the (+ X) side. Since the imaging unit 91 is arranged in a direction perpendicular to the imaging region Ri, the regular reflection light from the imaging region Ri does not enter the imaging unit 91.

  When specularly reflected light of illumination light enters the imaging unit 91, halation occurs and image information is lost, making it impossible to obtain an appropriate image according to the density of the imaging region. Illumination light is incident from an oblique direction as described above, and the imaging unit 91 is disposed at a position off the optical path of the regular reflection light of the illumination light, thereby preventing regular reflection light from entering the imaging unit 91. Generation of halation can be avoided.

  It should be noted that the fact that the optical axis of the imaging unit 91 is perpendicular to the surface of the substrate S is not an essential requirement in terms of preventing regular reflection light from entering the imaging unit 91. As shown in FIGS. 3B and 3C, as long as the imaging unit 91 is provided at a position deviated from the optical path of the regular reflection light of the illumination light in the imaging region Ri, the optical axis of the imaging unit 91 is based. It may be inclined with respect to the surface of the material S. However, in the configuration in which the optical axis of the imaging unit 91 is inclined with respect to the surface of the substrate S, the variation in the width direction of the end position of the coating film F has a component in the optical axis direction of the imaging unit 91. Therefore, consideration must be given to prevent the end portion from being out of focus range.

  From the viewpoint of avoiding the incidence of regular reflection light, there may be a case where the optical axis of the imaging unit 91 is inclined with respect to the optical path of the regular reflection light emitted from the imaging region Ri at the largest reflection angle. However, for the purpose of detecting the position of the end portion Rf of the coating film F, it is preferable to image the surface of the substrate S from a direction as perpendicular as possible. As shown in FIG. 3A to FIG. 3C, a range of a region serving as an optical path of illumination light emitted from the illumination unit 93 toward the imaging region Ri, and regular reflection light emitted from the imaging region Ri. It is desirable that the imaging unit 91 be provided between the range of the region serving as the optical path. As will be described below, this is also a request for avoiding the incidence of regular reflection light from the coating film F when the coating film F is formed on the surface of the substrate S.

  FIG. 4 is a diagram showing an optical path of specularly reflected light when a coating film is formed on the substrate surface. From the viewpoint of keeping the thickness of the coating film F constant up to the end, it is desirable that the end surface of the coating film F stands upright with respect to the surface of the substrate S. However, in the coating method of forming the coating film F by discharging the coating liquid from the nozzle 5 having the slit-shaped opening, as shown in FIG. 4A, the coating film F is formed by the surface tension of the coating liquid. The end portion is rounded, and the surface thereof has a gradient such that the normal direction includes a component toward the outside of the coating film F in the width direction Dw. The magnitude of the gradient and the width of the range in which the gradient is generated are determined by the viscosity of the coating liquid and the wettability with respect to the substrate S.

  In a state where the right end Rf of the coating film F is included in the imaging region Ri, a part L2 of the illumination light incident on the imaging region Ri from the illumination unit 93 enters the flat surface of the coating film F. The surface of the coating film F in an undried state has a high reflectance, and a strong regular reflection light is emitted. Since the surface of the coating film F is substantially parallel to the surface of the substrate S, the emission direction of the specular reflection light is substantially the same as the emission direction of the specular reflection light on the surface of the substrate S. If the regular reflection light on the surface of the substrate S is not incident on the imaging unit 91, the regular reflection light from the coating film F also does not enter the imaging unit 91. Further, the other part L3 of the illumination light incident on the imaging region Ri is incident on the exposed surface of the substrate S that is not covered with the coating film F and is regularly reflected. This regular reflection light also does not enter the imaging unit 91.

  On the other hand, the illumination light L4 incident on the end portion Rf having a gradient on the surface is regularly reflected at a larger emission angle than when incident on the surface of the substrate S. That is, when attention is paid to the direction component parallel to the width direction Dw and directed from the central portion of the coating film F toward the end portion Rf, the specularly reflected light has a larger direction component than the direction component of the incident light. . For this reason, with respect to the imaging unit 91 arranged with a smaller inclination than the direction of the optical path of the regular reflection light on the surface of the substrate S, the regular reflection light at the end Rf is emitted in a direction away from the imaging unit 91. There is no incident.

  As shown in FIG. 4B as a comparative example, for this type of imaging, ring illumination RI provided so as to surround the optical axis of the imaging unit 91 has been put into practical use. When such a ring illumination RI is used for the purpose of imaging the end portion Rf of the coating film F, the direction from the end portion Rf side of the coating film F toward the central portion side in the direction parallel to the width direction Dw, FIG. , The illumination light L5 having a component in the (−X) direction may be regularly reflected by the end Rf and enter the imaging unit 91. As a result, halation occurs, and the position of the end portion Rf cannot be detected from the image.

  As in the present embodiment, illumination light that has a directional component from the center side of the coating film F toward the end Rf side in a direction parallel to the width direction Dw and substantially does not have a component in the opposite direction. By using this, it becomes possible to avoid the problem of halation and to image the end portion Rf of the coating film F satisfactorily.

  FIG. 5 is a diagram illustrating items to be further considered in imaging. Specifically, FIG. 5A is a diagram showing the end position of the coating film detected from the captured image, and FIG. 5B is the contact angle of the coating film and the incident direction of illumination light. It is a figure which shows the relationship. When the end of the coating film F formed as a flat film on the surface of the substrate S is a curved surface, it may be a problem which position is defined as the “end position”. For the purpose of stably controlling the amount of film material supplied to the substrate S, it is sufficient to obtain the change in the width of the coating film F from the position detection result. As long as it is uniquely defined as, it is arbitrary which position is the end position. For example, a position where a flat portion that continues from the center of the coating film F terminates as a position A shown in FIG. 5A may be set as an end position, and a coating film F like a position B may be used. The position where the surface of the substrate contacts the surface of the substrate S may be the end position.

  Further, like the light L6 shown in FIG. 5B, the illumination light having a relatively small incident angle (nearly perpendicular to the surface of the substrate S) is also incident on the curved surface portion of the end portion Rf of the coating film F. Therefore, this portion appears as a relatively bright image in the image. Under such illumination conditions, a difference in image density due to the difference in material between the substrate S and the coating film F is likely to appear, and therefore the position B where the surface of the coating film F and the surface of the substrate S are in contact with each other It is suitable for detecting the end position. On the other hand, the illumination light is incident from a direction having a larger incident angle, for example, an angle α formed with respect to the surface of the substrate S (or the surface of the coating film F) is smaller than a contact angle β of the coating film F with respect to the substrate S. In L7, the curved surface portion of the end portion Rf of the coating film F becomes dark due to the shadow of the coating film F itself. An image picked up under such illumination conditions is suitable for detecting a position A where the gradient of the surface of the coating film F changes. In this way, the definition of the illumination direction and the end position can be appropriately set according to the purpose.

  FIG. 6 is a flowchart showing an outline of the coating process in this embodiment. This process is realized by the control unit 3 executing a control program created in advance and causing each part of the apparatus to perform a predetermined operation.

  A coating liquid supply amount for obtaining a necessary basis weight is set in advance (step S101). Then, the conveyance of the base material S is started by the rotation of the winding roller 74 (step S102), and the coating liquid corresponding to the set coating liquid supply amount is sent from the pump 22 to the base material S from the nozzle 5. The coating liquid is applied (step S103). At this time, both ends Rf and Lf of the formed coating film F are periodically imaged by the imaging unit 9 (step S104), and the positions of both ends are detected each time (step S105). The width (coating width) of the coating film F on the surface of the base material S is calculated from the both end positions thus detected (step S106).

  The processing after step S103 is continued until the application of the predetermined length is completed (step S107). At this time, it is determined whether or not the calculated coating width is within a predetermined specified range (step S108). If the calculated coating width is out of the specified range (NO in step S108), the application liquid supply amount is set. Is changed (step S109). If the coating width is within the specified range (YES in step S108), the coating is continued as it is. When the application for a predetermined length is completed (YES in step S107), the discharge of the coating liquid from the nozzle 5 and the conveyance of the substrate S are stopped (step S110), and the process is completed.

  Next, a modification of each part of the coating apparatus 100 configured as described above will be described with reference to FIGS. In the following description, the same components as those in the above embodiment are denoted by the same reference numerals or illustrations are omitted, and the description thereof is omitted. Unless otherwise specified, the same configurations as those in the above embodiment are as follows. It is assumed that the modification is also provided.

  FIG. 7 is a diagram showing a modification of the illumination unit. In the description so far, the illumination units 93 and 94 have bar-shaped illumination light sources, and conventionally used ring illumination is not preferable as an illumination light source. However, it is also possible to perform imaging using a ring illumination instrument by doing the following. As shown in FIGS. 7A and 7B, (−) of the imaging region Ri in the width direction Dw in the light exit surface of the illumination unit 95 using a ring illumination provided in place of the illumination unit 93 as a light source. X) By leaving only the portion 951 further on the (−X) side than the end portion on the side and covering the other portion 952 with the shielding member 953, light incident on the imaging region Ri from this portion 952 is shielded. According to such a configuration, illumination light having a directional component from the central portion to the end portion of the coating film F in the horizontal direction D can be incident on the imaging region Ri in the same manner as in the above embodiment. Thereby, it is possible to avoid the specularly reflected light from the coating film F from entering the imaging unit 91.

  FIG. 8 is a diagram illustrating a modification of the imaging unit. In the above embodiment, the imaging regions Ri and Li are individually set for the right end Rf and the left end Lf of the coating film F, and two sets of imaging units 91 and 92 are provided correspondingly. However, one set of imaging unit may be used. For example, as shown to Fig.8 (a), the structure which images the both ends of the coating film F collectively with the single imaging part 96 which has a comparatively wide angle and a wide imaging range may be sufficient.

  Moreover, as shown in FIG.8 (b), imaging may be performed by the linear image sensor 97 which makes the width direction (X direction) of the base material S a longitudinal direction. This is because the substrate S is conveyed in the Y direction orthogonal to the longitudinal direction of the linear image sensor 97, so that a substantially two-dimensional image is obtained. For the purpose of detecting the end position of the coating film F, a two-dimensional image is not essential.

  Also in these modified examples, the illumination units 93 and 94 of the above embodiment can be used as they are. For example, a single unit that emits light radially from the upper center of the coating film F toward both ends Rf and Lf. The light source may be used as the illumination unit. In these cases, the illuminating part is reflected in the captured image, but there is no problem for the purpose of detecting the positions of these end parts as long as the end parts Rf and Lf of the coating film F are not shielded. .

  The coating apparatus 100 of the said embodiment is an apparatus which forms the single coating film F on the surface of the elongate sheet-like base material S. FIG. However, in this type of coating apparatus, there is one in which a plurality of strip-shaped coating films whose longitudinal direction is the transport direction of the base material are formed side by side in the width direction of the base material. In the configuration shown in FIG. 1 as well, it is possible to form such a coating film by dividing the opening of the nozzle 5 into a plurality of parts, or by arranging a plurality of nozzles facing the substrate S. is there.

  FIG. 9 is a diagram showing a case where a plurality of coating films are formed side by side on a substrate. In such a case, as shown in FIG. 9A, a plurality of coating films F are formed so as to be arranged at a predetermined interval in the width direction (X direction) of the substrate S. In order to detect the end position of each coating film F, an imaging unit 9 corresponding to each coating film F is required. Then, as shown by a broken line in FIG. 9A, for example, the lights L8 and L9 emitted from the illumination unit 93 corresponding to one coating film and reflected by the surface of the coating film F or the base material S There is a possibility that the light enters the imaging unit 92 provided corresponding to the coating film.

  To solve this problem, as shown in FIG. 9B, a light shielding plate 98 for preventing stray light from the adjacent imaging unit 9 from entering the imaging unit between the plurality of imaging units 9 is provided. It is conceivable to provide it. By doing so, it is possible to avoid the disappearance of image information due to stray light that enters the imaging unit from other imaging units, particularly specularly reflected light. Thereby, it becomes possible to detect the edge part position of each coating film F appropriately, respectively.

  FIG. 10 is a top view showing another example in which a plurality of imaging units are arranged. More specifically, FIGS. 10A and 10B show two examples of the arrangement of the four sets of imaging units 9 provided for the four coating films F. FIG. In these modified examples, the imaging units 9 corresponding to each of the adjacent coating films F are arranged at different positions in the Y direction, which is the transport direction Ds of the base material S. Specifically, in the example illustrated in FIG. 10A, four sets of imaging units 9 are arranged with positions different from each other in the transport direction Ds of the base material S, that is, the Y direction. In the example shown in FIG. 10B, four sets of imaging units 9 are in a so-called staggered arrangement so that adjacent imaging units 9 are located at different positions in the Y direction. Even with such a configuration, it is possible to prevent image information from being lost due to stray light incident from another imaging unit.

  As described above, in the above embodiment, the transport unit 7 functions as the “transport means” of the present invention, and the tank 1, the liquid feeding system 2 and the nozzle 5 are integrated as “application means” of the present invention. It is functioning. In the imaging unit 9, the imaging units 91 and 92 and the imaging units 96 and 97 in the modification function as “imaging unit” of the present invention, and the illumination units 93, 94, and 95 function as “illumination unit” of the present invention. doing. The light emitting surfaces 931 and 941 function as the “light irradiator” of the present invention. Further, the control unit 3 functions as the “position detecting means” of the present invention. Further, the light shielding plate 98 functions as the “light shielding member” of the present invention.

  Further, in the operation of the above embodiment, Step S103, Step S104, and Step S105 correspond to the “application process”, “imaging process”, and “position detection process” of the present invention, respectively.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, the illumination unit in the above embodiment uses a bar-like light source or a ring-shaped one partially shielded, but a light source that can be regarded as a point light source or a surface light source may be used. For light emitted from the light source in a direction that does not satisfy the above-described conditions, the direction may be changed by shielding or reflecting the light.

  Further, in the above embodiment, two sets of illumination units 93 and 94 are provided corresponding to both end portions Rf and Lf of the coating film F, but these may be integrated. For example, a configuration in which illumination light incident on each of the two imaging regions Ri and Li is generated from a single light source by a reflection mirror or the like may be used.

  Moreover, in the said embodiment, although it becomes the structure which detects the both ends position of the coating film F in order to calculate coating width, when performing the position detection of the one end part of the coating film F, for example, The present invention can be effectively applied.

  In the above embodiment, still images are taken periodically and intermittently by the imaging units 91 and 92, but the end position of the coating film is detected from an image captured by moving images. Good.

  Moreover, in the said embodiment, although the electrode for batteries is manufactured using the metal film used as a collector as the base material S and the active material as the coating film F, the base material and the coating object to be applied to this invention The material of the film (coating liquid) is not limited to this and is arbitrary.

  As described above, as a specific embodiment has been illustrated and described, in the coating apparatus according to the present invention, for example, the illumination unit includes a light irradiation unit that emits illumination light, and the light irradiation unit is You may arrange | position to the center part side of a coating film rather than an imaging region in the width direction. In such a configuration, the light traveling from the light emitting portion to the imaging region necessarily includes a directional component from the central portion to the end portion side of the coating film, thereby causing the regular reflection light to enter the imaging means. It can be easily avoided.

  Further, for example, the optical axis of the imaging unit may be perpendicular to the imaging region. According to such a configuration, the fluctuation in the width direction of the end position of the coating film appears perpendicular to the optical axis of the image pickup means, so that the end is also kept in the focusing range of the image pickup means due to the change. It is possible to detect the position of the end portion that fluctuates in the imaging region with certainty.

  Further, for example, the imaging unit may be configured to capture both ends of the coating film in the width direction, and the position detection unit may detect the positions of both ends of the coating film in the width direction. According to such a configuration, the width of the coating film can be obtained from the position detection results of both ends, and the result can be used for managing the basis weight, for example.

  In this case, when the coating unit forms a plurality of coating films in the width direction on the surface of the substrate, for example, a plurality of imaging units and a plurality of illumination units corresponding to each of the plurality of coating films. And a light-shielding member that shields light incident on the adjacent imaging area from the illumination means corresponding to one imaging area is provided between the illumination means provided corresponding to each of the adjacent coating films. May be. Alternatively, for example, illumination means provided corresponding to each of the adjacent coating films may be arranged at different positions in the transport direction. According to these configurations, the specularly reflected light caused by the light emitted from the illuminating means provided corresponding to the other imaging areas is incident on the imaging means, and the detection accuracy of the end position is hindered. It can be prevented in advance.

  Moreover, the coating apparatus and the coating method concerning this invention may form the coating film which contains an active material in the base material which has a metal film which functions as a collector, for example. According to such a configuration, it is possible to manufacture an electrode of a chemical battery in which a current collector layer and an active material layer are laminated. In battery electrodes, the weight of the active material affects the battery capacity, so its management is important. Also, the coating film (active material layer) after drying has a relatively low light reflectance while being used. Since the liquid generally has a high viscosity and a high reflectance, the effect of the present invention is particularly remarkable.

  Further, for example, the imaging unit may be configured to image the surface of the base material that is transported in a flat state by the transport unit. In such a configuration, since the imaging region can be a flat surface, it is easy to manage the emission direction of the reflected light.

  Further, for example, the conveying means may convey a long sheet-like base material by a roll-to-roll method. According to such a configuration, it is possible to continuously form a coating film on a long base material, and the coating film is formed in a state where the end position in the width direction is always grasped. be able to.

  For example, the amount of the coating liquid supplied to the substrate may be controlled based on the result of position detection. According to such a configuration, the width of the coating film formed by the amount of the coating liquid can be controlled in real time, and a coating film with a stable basis weight can be obtained.

  The present invention is applicable to all techniques for forming a coating film by applying a coating solution to a sheet-like substrate.

1 Tank (application means)
2 Liquid feeding system (coating means)
3 Control unit (position detection means)
5 Nozzles (application means)
7 Transport unit (transport means)
9 Imaging unit 91, 92, 96, 97 Imaging unit (imaging means)
93, 94, 95 Illumination part (illumination means)
98 Shading plate (shading member)
100 Coating device 931, 941 Light exit surface (light irradiation part)
S103 Application process S104 Imaging process S105 Position detection process

Claims (12)

Conveying means for conveying a sheet-like base material;
A coating means for continuously coating a coating liquid on the surface of the substrate to be conveyed to form a substantially flat coating film;
An imaging region that is arranged toward the surface of the base material and includes an end portion of the coating film in a width direction that is parallel to the surface of the base material and orthogonal to the transport direction of the base material among the surfaces of the base material Imaging means for imaging the interior;
Illuminating means for irradiating illumination light toward the imaging region;
A position detection unit that detects a position of the end in the width direction based on an image captured by the imaging unit;
The incident direction of the illumination light to the imaging area is parallel to the normal direction of the imaging area and from a direction component from the imaging means to the imaging area, and parallel to the width direction from the center of the coating film. A direction component having a directional component toward the end,
The imaging means receives the light from the imaging region at a position between the optical path of the illumination light incident on the imaging region and the optical path of the regular reflection light of the illumination light from the imaging region. .   The said illumination means has a light irradiation part which radiate | emits the said illumination light, This light irradiation part is arrange | positioned in the said width direction at the center part side of the said coating film rather than the said imaging region. Coating equipment.   The coating apparatus according to claim 1, wherein an optical axis of the imaging unit is perpendicular to the imaging region.   4. The image capturing unit according to claim 1, wherein the imaging unit images both ends of the coating film in the width direction, and the position detection unit detects positions of both ends of the coating film in the width direction. 5. The coating apparatus as described in.   The coating means forms a plurality of the coating films in the width direction on the surface of the substrate, and a plurality of the imaging means and a plurality of the illumination means are provided corresponding to each of the plurality of coating films. In addition, a light shielding member that shields light incident on the adjacent imaging region from the illumination unit corresponding to one imaging region between the illumination units provided corresponding to each of the adjacent coating films. The coating apparatus according to claim 4 provided with.   The coating means forms a plurality of the coating films in the width direction on the surface of the substrate, and a plurality of the imaging means and a plurality of the illumination means are provided corresponding to each of the plurality of coating films. The coating device according to claim 4, wherein the illumination means provided corresponding to each of the adjacent coating films are arranged at different positions in the transport direction.   The coating apparatus according to claim 1, wherein the imaging unit images the surface of the base material that is transported in a flat state by the transport unit.   The coating apparatus according to any one of claims 1 to 7, wherein the transport unit transports the long sheet-like base material in a roll-to-roll manner. An application step in which a coating means continuously applies a coating solution on the surface of the substrate to be conveyed while conveying a sheet-like substrate by a conveying means to form a substantially flat coating film,
While illuminating illumination light from the illumination means to the imaging region including the edge of the coating film in the width direction that is parallel to the surface of the substrate and orthogonal to the transport direction of the substrate, among the surfaces of the substrate, An imaging step of imaging the imaging area by imaging means;
A position detecting step of detecting the position of the end in the width direction based on the image picked up by the image pickup means,
The incident direction of the illumination light to the imaging area is parallel to the normal direction of the imaging area and from a direction component from the imaging means to the imaging area, and parallel to the width direction from the center of the coating film. A direction component having a directional component toward the end,
The imaging means receives the light from the imaging area at a position between the optical path of the illumination light incident on the imaging area and the optical path of the regular reflection light of the illumination light from the imaging area. .   The coating method of Claim 9 which forms the said coating film containing an active material in the said base material which has a metal film which functions as a collector.   The coating method according to claim 9 or 10, wherein the transport means transports the long sheet-like base material in a roll-to-roll manner.   The coating method according to claim 9, wherein an amount of the coating liquid supplied from the coating unit to the base material is controlled based on a detection result in the position detection step.