JP5679866B2 - Coating apparatus and coating method - Google Patents

Description

  The present invention relates to a coating apparatus and a coating method for applying a coating liquid on a substrate and forming a thin film on the substrate.

  A technique for forming a thin film by applying a coating liquid on a substrate by discharging it from a slit nozzle that moves relative to the substrate has been known for a long time. This coating technique is utilized in many fields including flat panel displays such as liquid crystals. In this coating technique, it is necessary to form a bead by the coating liquid between the slit nozzle and the substrate in order to continuously discharge the coating liquid from the slit nozzle during the movement, while moving the substrate and the slit nozzle relatively. In order to maintain the bead, it is necessary to set the distance between the substrate and the slit nozzle as narrow as about 100 to 200 μm, for example.

  However, foreign substances such as particles are not completely removed although the substrate before coating is cleaned. If coating is performed in the presence of foreign matter, the slit nozzle collides with the foreign matter or the substrate due to the foreign matter itself or the penetration of the foreign matter under the substrate, damaging the substrate or the slit nozzle or interrupting the supply of the coating liquid. Problems occur. In order to prevent this, as in Patent Document 1, a technique for detecting foreign matter by various means including laser light before coating has been proposed.

  This foreign matter detection technology, particularly the technology using laser light, was effective in detecting accuracy and downsizing the device, but in recent years the substrate size has increased due to an increase in large liquid crystal TVs and the coating width exceeds 2 m. Various things have arisen under the circumstances where it has become necessary to project such a long distance with a laser beam. One of these problems is a decrease in detection accuracy due to disturbance. Basically, as described above, the coating apparatus is damaged by the foreign matter, and in the production line, clean air is supplied from the ceiling or the like to keep the coating apparatus and its surroundings clean, and the foreign matter is removed. Since this clean air flows instead of staying, there is a situation in which the detection accuracy is reduced due to disturbance such as scattering of the irradiation laser beam due to the flow. As shown in Patent Document 2, a countermeasure for installing a cover over the entire length of the optical axis has been proposed for the problem of reduced accuracy of foreign object detection due to disturbance including the above problems. However, it is difficult to manufacture a light and highly rigid long cover. Conversely, a cover that is stiff but heavy is an extra load on the applicator and causes the application accuracy to go wrong.

Japanese Patent No. 4325084 Japanese Patent No. 4562190

  The present invention overcomes the above-mentioned problems and prevents a decrease in detection accuracy due to disturbance such as disturbance of laser light due to the surrounding airflow even when laser light is irradiated at a distance exceeding 2 m for detecting foreign matter on the substrate. It is an object of the present invention to provide a coating apparatus and a coating method having a shielding device with excellent processability.

In order to solve the above problems, the coating apparatus of the present invention scans the substrate by moving relative to the sheet-like substrate, and discharges the coating liquid on the substrate surface to form a coating film on the substrate surface. And a coating device that includes at least a detection device that is disposed upstream of the ejection device in the scanning direction and detects foreign matter on the substrate, wherein the detection device emits laser light parallel to the substrate surface. a device, a light receiving device for receiving the projected by laser light, and have a shielding device for shielding the air flow of the laser beam immediately after being projected from at least the light emitting device, the shielding device, It is characterized in that it is provided so as to close a gap formed between a stage on which the substrate is placed and a base that supports the stage .

  According to the shielding device of the present invention, it is easy to process and attach, and at the same time, it is possible to suppress the disturbance of the laser beam due to the air flow. As a result, it is possible to reliably detect foreign matter that causes damage to the substrate and the slit nozzle.

  Specifically, the shielding device may be configured to shield a region immediately below the laser beam immediately after the projection.

  Further, the coating apparatus of the present invention is characterized in that the shielding device suppresses and shields the air flow that affects the detection device without shielding the laser optical axis itself. According to this configuration, it is possible to manufacture the shielding device more compactly by suppressing the disturbance of the laser beam by performing the minimum shielding.

Furthermore, the coating method of the present invention scans the sheet-like substrate by moving relative to the sheet-like substrate, and discharges a coating liquid onto the surface of the sheet-like substrate, thereby forming a coating film on the surface of the sheet-like substrate. A discharge step of forming, and a detection step of detecting a foreign matter on the sheet-like substrate on the upstream side in the scanning direction in the discharge step, wherein the detection step projects light that irradiates a laser beam parallel to the substrate surface, Including a light receiving step for receiving the projected laser beam, and closing a gap formed between a stage on which the substrate is placed and a base supporting the stage, at least directly below the light projecting area. It is characterized by shielding the air flow.

  According to the coating method of the present invention, the processing and mounting are easy, and if the air flow is shielded, it is possible to suppress the disturbance of the laser beam, and as a result, foreign matter that causes damage to the substrate and the slit nozzle. Can be reliably detected.

  According to the coating apparatus and the coating method of the present invention, a stable coated substrate can be produced without damaging the slit nozzle and / or the substrate due to foreign matter.

It is a perspective view of the coating device containing the shielding apparatus of this invention. It is explanatory drawing which shows the relationship between a foreign material and a nozzle | cap | die. It is a front view which shows the Example containing the shielding apparatus of this invention.

  Embodiments relating to the coating apparatus of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing an outline of an embodiment of a coating apparatus having a foreign matter detection apparatus of the present invention. In FIG. 1, a coating apparatus 1 includes a base 11, a stage 21 that fixes a substrate 10, a discharge device 30 that discharges a coating liquid and discharges the coating liquid onto the substrate 10 to form a coating film, and a foreign matter detection device 40. ing.

  In the present embodiment, the coating liquid is applied onto the substrate while the ejection device 30 performs scanning on the substrate 10, and the scanning direction is the X direction (also referred to as the application direction), and is orthogonal to the horizontal plane. The direction to be performed is the Y-axis direction, the direction orthogonal to both the X-axis and the Y-axis directions is the Z-axis direction, and in FIG. 2, the right direction is the downstream side and the left direction is the upstream side.

  The base 11 and the stage 21 are made of stone, ceramic, or metal structure. The substrate 10 is a thin plate made of glass or the like, and is carried into the stage 21 by a carrying-in device (not shown) such as a robot. At that time, lift pins (not shown) are incorporated in the stage 21 in order to receive the substrate 10 carried from the carry-in device. When the carry-in apparatus transfers the substrate 10 to the lift pins, the lift pins descend and place the substrate 10 on the stage 21.

  The stage 21 is further provided with a substrate positioning mechanism (not shown), and positions the substrate 10 placed on the stage 21 in the X and Y directions. A plurality of suction holes (not shown) are formed in the stage 21, and the substrate 10 positioned by the positioning mechanism by vacuum suction of the substrate 10 through a vacuum pump (not shown) is placed on the stage 21. Fix it. The discharge device 30 is a device that has a portal shape and applies the coating liquid to the substrate 10. The base 31 discharges the coating liquid, the side plate 32 that supports the gate structure, the stay 33 that supports the base 31, and the base lifting mechanism 34. It is composed of

  The base 31 has a slit-like discharge port, and discharges the coating liquid from the discharge port to the substrate 10 while scanning the substrate 10 in the X direction in accordance with the movement of the discharge device 30 in the X direction. The base 31 has a stay 33 attached to the upper portion thereof for improving straightness and operability. The base 31 moves in the Z direction between the application position and the standby position, and the movement is performed by the base lifting mechanism 34. The base raising mechanism is composed of a combination of driving means such as a motor and linear motion means, or linear driving means such as a linear motor. An application liquid supply mechanism 50 for supplying an application liquid is connected to the base 31 by a pipe 53. The coating liquid supply mechanism 50 includes a coating liquid supply tank 54, a buffer tank 51, a control valve 52, and a pipe 53. The coating solution stored in the coating solution supply tank 54 is sent to the buffer tank 51 by means of compressed air or the like and temporarily stored. Next, the control valve 52 opens and closes according to a signal output from a control unit (not shown) of the coating apparatus 1 according to the coating state, and sends the liquid to the coating liquid supply tank 54. The coating liquid supply tank 54 sends the coating liquid for one substrate to the base 31 according to the coating operation.

  FIG. 2 is a schematic explanatory diagram showing the relationship between the base and the foreign matter. The discharge device 30 performs a linear motion by a drive device (not shown) such as a linear motor, and discharges the coating liquid from the base 31 while moving on the substrate 10 in the X direction. At that time, the distance between the tip of the base 31, that is, the tip of the coating liquid discharged from the substrate 10 is set to about 100 μm. Therefore, when the foreign material 49a is present on the substrate 10 as shown in FIG. 2 or when the foreign material 49b has entered the lower side of the substrate 10, the discharge device 30 performs the scanning as described above. There is a possibility that the tip of 31 contacts the foreign substance 49a itself or the substrate 10 raised by the penetration of the foreign substance 49b, and bites in the worst case. Such biting may cause damage to the base 31 as well as the substrate 10 depending on the type of foreign matter.

  In order to prevent this biting, the foreign object detector 40 is installed, but there is a technical problem with foreign object detection using laser light as described above. Therefore, the foreign object detection device 40 of the present invention will be described in detail below with reference to FIGS.

  As shown in FIG. 3, the foreign object detection device 40 includes a projector 43a, a light receiver 43b, a control device 41, a control / power wiring 42, a shielding device 45a, and a shielding device 45b. The projector 43a is composed of a laser oscillator and an irradiation optical system. The laser light (class 2) having an output of 0.7 mW and a wavelength of 670 nm is adjusted to be approximately parallel light by the irradiation optical system and is projected in the direction of the optical axis 46. The light receiver 43b has a photodiode and receives the laser light projected from the projector 43a. Here, when there is the foreign matter 49a or the foreign matter 49b, all or a part of the projected laser beam hits the foreign matter 49a or the foreign matter 49b and is reflected or scattered. As a result, the laser beam received by the light receiver 43b is reduced compared to the case where there is no foreign object 49a or foreign object 49b. The control device 41 compares the light reception signal transmitted from the light receiver 43b via the control / power wiring 42 and transmits it as foreign matter information to a control unit (not shown) of the coating device 1, whereby the coating device 1 determines whether or not there is a foreign matter. It can be judged. The control / power wiring 42 is composed of a plurality of harnesses, and is used for transmitting and receiving the power and drive signals of the projector and the light receiver in addition to the signals.

  The shielding devices 45a and 45b are made of a metal or resin thin plate member, and are arranged on the base 11 as shown in FIGS. 1 and 3 along the application direction of the light projector 43a and the light receiver 43b, respectively. is set up. That is, the shielding devices 45a and 45b have a gap between the base 11 and the stage 21, and are provided so as to close the gap. In the present embodiment, this gap is formed in a region immediately below the laser beam projected from the projector 43a, and the shielding device 45a is disposed so as to block this region. Similarly, a gap is also formed in the region immediately below the laser beam received by the light receiver 43b, and the shielding device 45b is disposed so as to close this region.

  In general, clean air for removing foreign substances is blown out from above the coating apparatus 1, whereby clean air flows in front of the projector 43 a and the light receiver 43 b, passes through the gap between the stage 21 and the base 11, and below the stage 21. Is passing through the space. In general, in a production line for liquid crystal panels or the like, a structure is used in which a floor is covered with a perforated panel except for a place where it is necessary to support a heavy object just below the apparatus. As a result, the clean air blown out from above the coating apparatus 1 flows out under the floor, and a clean air flow can be formed around the coating apparatus 1. However, the air flow path is not formed uniformly, and the air flow is concentrated in a specific flow path, so that the flow speed may be increased in the air flow path. Under such circumstances, when these air flows are formed between the projector 43a and the light receiver 43b, the laser light projected from the projector 43a is subject to obstacles such as scattering.

  For this reason, the shielding devices 45a and 45b are arranged so as to close the gap between the base 11 and the stage 21 so as to prevent the air flow path. The shielding devices 45 a and 45 b may be provided in the discharge device 30, but in this case, in order to suppress the generation of an air flow due to the scanning of the discharge device 30, it is necessary to increase the size as compared with the case where it is installed on the base 11. Further, according to the experimental results, the influence of the air flow on the laser beam is larger on the light projecting side, so the light receiving side shielding device is omitted depending on the setting conditions such as target detection accuracy or the configuration of the coating apparatus 1 or the floor structure. You may do it.

  As described above, if the foreign matter detection device having the shielding device of the present embodiment is adopted in the coating device, accidents such as breakage of the base due to foreign matter in the coating process are greatly increased even when a large substrate exceeding 2 m wide is applied. Reduced and stable production becomes possible. In addition, even in a coating apparatus that coats a substrate having a width of 2 m or less, stable production more than conventional can be expected.

  In the present embodiment, the coating apparatus 1 has a mechanism in which the stage 21 is fixed and the discharge apparatus 30 scans the substrate 10 that is suction-fixed on the stage 21. However, the discharge apparatus 30 is fixed and the stage 10 is fixed. A driving method may be used. Also in this case, the structure of the shielding devices 45a and 45b can be made the same as in this embodiment. Further, although the ejection device 30 of this embodiment is a slit nozzle mechanism, the ejection mechanism may be other mechanisms such as an inkjet mechanism or a slot coating dispenser. Even if the coating mechanism 1 is other than the slit nozzle, the shielding devices 45a and 45b can be the same as in this embodiment.

DESCRIPTION OF SYMBOLS 1 Coating device 10 Substrate 11 Base 21 Stage 30 Discharge device 31 Base 32 Side plate 33 Stay 34 Base raising mechanism 40 Foreign object detection device 43a Projector 43b Receiver 45a Shielding device (projection side)
45b Shielding device (light receiving side)
49a Foreign object (top)
49b Foreign object (bottom)
50 Coating liquid supply mechanism 51 Buffer tank 52 Control valve 53 Piping 54 Coating liquid supply tank

Claims (3)

A discharge device that scans the substrate by moving relative to the sheet-like substrate and forms a coating film on the substrate surface by discharging a coating liquid on the substrate surface, and is disposed upstream of the discharge device in the scanning direction. A coating device having at least a detection device for detecting foreign matter on the substrate, wherein the detection device irradiates a laser beam parallel to the substrate surface, and a light-receiving device that receives the projected laser beam. When, and have a shielding device for shielding the air flow of the laser beam immediately after being projected from at least the light emitting device,
The said shielding apparatus is provided so that the clearance gap formed between the stage which mounts the said board | substrate and the base which supports this stage may be plugged up . The coating apparatus according to claim 1, wherein the shielding device shields a region immediately below the laser beam immediately after the projection. A discharge step of scanning the sheet-like substrate by moving relative to the sheet-like substrate and forming a coating film on the surface of the sheet-like substrate by discharging a coating liquid onto the surface of the sheet-like substrate; and the discharge step wherein a detection step of detecting a scanning direction upstream side foreign matter of the sheet-like substrate of the said detection step is projecting the light by irradiating a laser beam parallel to the substrate surface, the projected by laser beam Including a light receiving step for receiving light, and blocking at least an air flow immediately below the light projecting region by closing a gap formed between a stage on which the substrate is placed and a base supporting the stage. A characteristic coating method.

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