JP2012143729A - Print coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a print coating method capable of, for example, applying orientation film to a glass substrate with high flatness and narrowing a frame area as much as possible.SOLUTION: With the inside of a chamber maintained under a decompression state, ink INK is applied to only the outer periphery of a glass substrate GS disposed on a stage. Subsequently, after the pressure in the chamber is recovered to be the atmospheric pressure (normal pressure), ink INK is more applied to the inner periphery of being an inward area than to the outer periphery, of a glass substrate GS disposed on the stage with the inside of the chamber maintained under a decompression state.

Description

  The present invention relates to a printing application method, and more particularly to a technique effective when applied to a printing application method for printing a film on a substrate using an inkjet head.

  Japanese Patent Laying-Open No. 2006-289355 (Patent Document 1) describes a technique of applying ink to a substrate using an inkjet head under a reduced pressure lower than atmospheric pressure. Specifically, a technique for applying (printing) an alignment film used for a liquid crystal display device on a glass substrate by using an inkjet head in a reduced pressure state lower than atmospheric pressure is described.

JP 2006-289355 A

  Various display elements, semiconductor devices, and the like are configured using various types of thin films. Of these thin films, an alignment film in a liquid crystal display device will be described below as an example.

  Liquid crystal display devices, which have great advantages as products of thin and light weight and low power consumption, have been greatly developed as mainstreams of mobile phones, personal computers, or thin televisions. A liquid crystal display device sandwiches a liquid crystal composition between two glass substrates on which electrodes are formed, and changes the molecular arrangement of the liquid crystal by applying a voltage between the two electrodes, thereby causing light to travel straight, Utilizing the phenomenon of blocking, an image is displayed in combination with a polarizing plate. At this time, the alignment film has a role in which the liquid crystal defines the molecular arrangement. That is, when the pretilt angle (angle formed between the molecular axis of the liquid crystal molecules and the surface of the alignment film) is given to the liquid crystal molecules in advance, the thin film surface of the alignment film plays an important role, and lightly rubs with a cloth after forming the thin film. (Rubbing treatment) realizes liquid crystal molecular alignment in a certain direction. The role of the alignment film is also important for uniform display, and flatness of the alignment film is required. In addition, the molecular alignment of liquid crystals is closely related to display performance such as brightness and viewing angle, and in order to improve these characteristics, it is an important issue to form an alignment film with good flatness. . That is, it is important to apply the alignment film to the glass substrate with good flatness in order to improve the characteristics of the liquid crystal display device.

  Further, in the liquid crystal display device, in order to increase the display area, there is a demand for making the frame region of the glass substrate where the liquid crystal display portion is not formed as narrow as possible. Therefore, also in the alignment film application process in which the alignment film described above is applied to the glass substrate, it is necessary to make the frame region where the alignment film is not formed as narrow as possible. The alignment film coating process is performed by, for example, flexographic printing technology or inkjet printing technology. However, with current flexographic printing technology and inkjet printing technology under normal pressure (atmospheric pressure), the positional accuracy on the end face of the alignment film is high. Due to problems, it has not been possible to reduce the frame area. On the other hand, in the inkjet printing technology under reduced pressure (30 kpa), since the printing position accuracy of the alignment film can be improved, the frame region can be narrowed, but if the glass substrate has a through hole or a pattern step, Under these influences, there is a problem that irregularities are formed on the surface of the alignment film. In other words, the inkjet printing technique under reduced pressure has a problem in that the alignment film cannot be applied to the glass substrate with good flatness, and as a result causes display unevenness in the liquid crystal display device.

  An object of the present invention is, for example, to provide a print coating method capable of coating an alignment film on a glass substrate with good flatness and making the frame region as narrow as possible.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  In a typical embodiment, a printing application method includes a chamber, a stage provided in the chamber, a substrate disposed on the stage, and an inkjet head provided in the chamber, and the inkjet The present invention relates to a print coating method in which ink is applied onto the substrate and a film is printed on the substrate by using a head. A specific print coating method includes: (a) a step of placing the substrate on the stage; (b) a step of setting the pressure in the chamber to a reduced pressure lower than atmospheric pressure after the step (a); Is provided. (C) After the step (b), using the inkjet head, the step of applying the ink to the outer periphery of the substrate; (d) After the step (c), the pressure in the chamber is set. And a step of bringing the pressure to atmospheric pressure. Further, (e) after the step (d), the same type of ink as that used in the step (c) is applied to the inner peripheral portion which is an inner region of the outer peripheral portion of the substrate using the inkjet head. And a step of applying the ink.

  In addition, a printing application method in a representative embodiment includes a first chamber, a first stage provided in the first chamber, a first inkjet head provided in the first chamber, and a second A chamber, a second stage provided in the second chamber, and a second ink jet head provided in the second chamber, and using the first ink jet head and the second ink jet head The present invention relates to a printing application method in which an ink is applied on a substrate and a film is printed on the substrate. The printing application method includes (a) a step of placing the substrate on the first stage provided in the first chamber, and (b) after the step (a), And a step of reducing the internal pressure to a reduced pressure state lower than the atmospheric pressure. And (c) after the step (b), using the first inkjet head provided in the first chamber to apply the ink to the outer periphery of the substrate; and (d) After the step (c), a step of unloading the substrate coated with the ink on the outer peripheral portion from the first chamber. Next, (e) after the step (d), the step of placing the substrate on the second stage provided in the second chamber whose internal pressure is at atmospheric pressure, and (f) the step (e) ) After the step, using the second inkjet head provided in the second chamber, the step of applying the ink to the inner peripheral portion which is the inner region of the outer peripheral portion of the substrate. Here, in the step (c), the ink applied to the outer peripheral portion of the substrate and the ink applied to the inner peripheral portion of the substrate in the step (f) are of the same type. It is characterized by being ink.

  Further, a printing application method in a representative embodiment includes a chamber, a stage provided in the chamber, a substrate disposed on the stage, and an inkjet head provided in the chamber, The present invention relates to a printing application method in which an ink is applied onto the substrate and a film is printed on the substrate by using the inkjet head. This printing application method includes (a) a step of placing the substrate on the stage, and (b) a step of setting the pressure in the chamber to a reduced pressure state lower than atmospheric pressure after the step (a). . (C) after the step (b), using the inkjet head, applying the ink to the first region of the substrate; (d) after the step (c), the pressure in the chamber A step of bringing the pressure to atmospheric pressure. Further, (e) after the step (d), the ink of the same type as the ink used in the step (c) is applied to the second region different from the first region of the substrate using the inkjet head. And a step of applying.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  For example, it is possible to provide a printing application method in which the alignment film can be applied to a glass substrate with good flatness and the frame region can be made as narrow as possible.

It is a figure which shows an example of the external appearance structure of the liquid crystal display device in Embodiment 1 of this invention. It is a figure which shows the structure of a liquid crystal display part. It is a figure explaining operation | movement of a liquid crystal display part. It is a figure explaining operation | movement of a liquid crystal display part. It is a flowchart which shows the flow of the manufacturing process which manufactures a liquid crystal display device. It is a figure explaining the 1st present technology. It is a figure explaining the 2nd present technology. It is a figure explaining the 3rd present technology. 1 is a diagram illustrating a configuration of an ink jet coating apparatus according to Embodiment 1. FIG. 3 is a flowchart for explaining the operation of the inkjet coating apparatus according to Embodiment 1. FIG. 5 is a diagram illustrating a characteristic process in the first embodiment. It is a figure explaining the characteristic process in the modification 1. It is a figure explaining the characteristic process in the modification 2. 10 is a flowchart for explaining a printing application method according to the second embodiment.

  In the following embodiments, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments. However, unless otherwise specified, they are not irrelevant to each other. There are some or all of the modifications, details, supplementary explanations, and the like.

  Further, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), especially when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and may be more or less than the specific number.

  Further, in the following embodiments, the constituent elements (including element steps and the like) are not necessarily indispensable unless otherwise specified and apparently essential in principle. Needless to say.

  Similarly, in the following embodiments, when referring to the shape, positional relationship, etc., of components, etc., unless otherwise specified, and in principle, it is considered that this is not clearly the case, it is substantially the same. Including those that are approximate or similar to the shape. The same applies to the above numerical values and ranges.

  In all the drawings for explaining the embodiments, the same members are denoted by the same reference symbols in principle, and the repeated explanation thereof is omitted. In order to make the drawings easy to understand, even a plan view may be hatched.

(Embodiment 1)
<External configuration of liquid crystal display device>
Liquid crystal display devices are widely used as display devices for televisions and mobile phones, including display devices such as personal computers and word processors. FIG. 1 is a diagram showing an example of an external configuration of the liquid crystal display device LCD according to the first embodiment. In FIG. 1, the liquid crystal display device LCD according to the first embodiment includes a liquid crystal display unit DU, a semiconductor chip CHP, and a flexible substrate FS. The liquid crystal display unit DU functions as a display unit that displays an image, and includes a plurality of liquid crystal display elements. The semiconductor chip CHP is configured to drive a plurality of liquid crystal display elements constituting the liquid crystal display unit DU, and an integrated circuit that controls the liquid crystal display unit DU to display an image is formed on the semiconductor chip CHP. Has been. The semiconductor chip CHP has a function of controlling on / off of a plurality of liquid crystal display elements constituting the liquid crystal display unit DU, and is called an LCD driver.

  The flexible substrate FS is equipped with many electronic components and is configured to control the liquid crystal display device LCD. Specifically, the flexible substrate FS is mounted with a plurality of semiconductor chips (semiconductor devices) on which CPUs and memories are formed, and passive elements such as resistors, capacitors, and inductors. For example, a semiconductor chip CHP which is an LCD driver is controlled by an electronic circuit mounted on the flexible substrate FS, and further, drive control of the liquid crystal display unit DU is performed by the semiconductor chip CHP, and an image is displayed on the liquid crystal display unit DU. Is displayed. The liquid crystal display device LCD according to the first embodiment is configured as described above. Next, a detailed configuration of the liquid crystal display unit DU will be described.

<Configuration of liquid crystal display>
FIG. 2 is a diagram illustrating a configuration of the liquid crystal display unit DU. As shown in FIG. 2, the liquid crystal display unit DU includes a plurality of liquid crystal display elements, and the liquid crystal display unit DU has the following configuration. That is, first, the liquid crystal display unit DU has a backlight BL made of, for example, a cold cathode fluorescent tube, and has a polarizing plate PL1 on the backlight BL. A TFT glass substrate TS is disposed on the polarizing plate PL1, and a color filter glass substrate CS is disposed on the TFT glass substrate TS through a space. Further, a polarizing plate PL2 is disposed on the color filter glass substrate CS, and a spacer (not shown) and liquid crystal LC are injected into a space provided between the TFT glass substrate TS and the color filter glass substrate CS. ing.

  The liquid crystal LC is a substance having an intermediate property between “liquid” and “solid”. “Crystal” refers to a substance in which molecules and atoms are regularly bonded to each other. “Liquid” refers to a state in which molecules and atoms are arranged separately and molecules and atoms are arranged irregularly. A substance. On the other hand, the “liquid crystal LC” is a substance having an intermediate arrangement between a crystal and a liquid, and is defined as a substance that behaves like a solid while being a liquid. That is, the molecules and atoms constituting the liquid crystal LC are basically arranged irregularly like a liquid, but are arranged regularly like a crystal in a certain direction. That is, the liquid crystal LC is defined as a substance having a lower regularity than a crystal but a higher regularity than a liquid. There are various types of liquid crystals in such a liquid crystal LC. For example, a liquid crystal LC in which long molecules constituting the liquid crystal LC are aligned in the major axis direction and molecules aligned in the major axis direction form a layer in the vertical direction is referred to as “smectic liquid crystal” and is simply the length of the molecule. The liquid crystal LC having the regularity that the axial direction is aligned in a certain direction is called “nematic liquid crystal”. Furthermore, there is a type of liquid crystal LC called “cholestic liquid crystal”. Thus, it can be seen that there are a plurality of types of liquid crystal LC due to the difference in the regularity of the molecular arrangement.

  The liquid crystal LC described above has a structure sandwiched between the TFT glass substrate TS and the color filter glass substrate CS. The configuration of the TFT glass substrate TS and the color filter glass substrate CS sandwiching the liquid crystal LC will be described.

  First, the TFT glass substrate TS has a glass substrate GS1 formed on the polarizing plate PL1, a TFT array TFA disposed on the glass substrate GS1, and an alignment film AF1 disposed on the TFT array TFA. Yes. Since the glass substrate GS1 needs to ensure the display performance of the liquid crystal display device LCD, unlike a general window glass, the glass substrate GS1 is required to have a very smooth surface and no surface waviness. That is, the glass substrate GS1 is composed of a glass substrate having a very high flatness. Furthermore, the glass substrate GS1 used for the liquid crystal display unit DU also has a difference in components from a general window glass. For example, a general window glass contains a large amount of sodium. However, when sodium is present in the glass substrate GS1, sodium contained in the glass substrate GS1 is melted as an impurity, and is formed on the surface of the glass substrate GS1. This adversely affects the TFT (Thin Film Transistor) to be formed. Therefore, as the glass substrate GS1 used for the liquid crystal display unit DU, a glass substrate with very high flatness is used, and so-called non-alkali glass or silica glass is used.

  Subsequently, a TFT array TFA is formed on the glass substrate GS1. The TFT array TFA includes a thin film transistor TFT formed for each pixel (liquid crystal display element) and an ITO electrode ITO1.

  In order to drive the liquid crystal LC, it is necessary to apply a voltage above and below the liquid crystal LC, and to apply a voltage above and below the liquid crystal LC, it is necessary to form electrodes on the glass substrate GS1. However, even if it says an electrode, if a normal metal electrode is formed, the normal metal electrode cannot transmit light. For this reason, it is necessary to form a transparent electrode with the substance which permeate | transmits light in the glass substrate GS which comprises liquid crystal display part DU. For this reason, the ITO electrode ITO1 is formed on the glass substrate GS. That is, since the ITO electrode ITO1 is a transparent electrode that can transmit light, it is used in the liquid crystal display unit DU. The ITO electrode ITO1 is made of indium and a small amount of tin oxide for reducing the resistance, and is attached to the glass substrate GS1 on the side in contact with the liquid crystal LC. The ITO electrode ITO1 is called the ITO electrode ITO1 after the acronym of indium / tin oxide. However, from the viewpoint of being transparent and conducting electricity well, the ITO electrode ITO1 can be composed only of inexpensive tin oxide. . However, in actuality, it is necessary to pattern the electrode itself. This is not so good when the patterning process is not oxidized. Therefore, the transparent electrode formed on the glass substrate GS1 uses the ITO electrode ITO1 that employs indium having good processability when patterning.

  As described above, the liquid crystal LC is driven by applying a voltage above and below the liquid crystal LC. That is, when a voltage is applied to the transparent electrodes (ITO electrodes) formed above and below the liquid crystal LC, the liquid crystal LC is driven using the fact that liquid crystal molecules rise straight. Therefore, in order to keep the liquid crystal molecules standing for a necessary time, it is desirable to sufficiently store charges in the transparent electrode. Thus, the thin film transistor TFT is formed from the viewpoint of accumulating a sufficient charge in the transparent electrode. That is, the thin film transistor TFT and the ITO electrode ITO1 are electrically connected. When the thin film transistor TFT is turned on, a current flows to the ITO electrode ITO1 through the turned on thin film transistor TFT, and charges are accumulated in the ITO electrode ITO1. Then, by turning off the thin film transistor TFT in this state, the electric charge accumulated in the ITO electrode ITO1 remains in the ITO electrode ITO1 as it is. As a result, electric charges can be accumulated in the ITO electrode ITO1 only for a necessary time, and thus, liquid crystal molecules can be reliably brought up for a necessary time. Therefore, it can be seen that the liquid crystal LC can be sufficiently driven by providing the thin film transistor TFT.

  Subsequently, an alignment film AF1 is formed on the glass substrate GS1 on which the TFT array TFA is formed. This alignment film AF1 is formed of, for example, a polyimide film, and is a film that has a role of aligning the direction in which liquid crystal molecules are arranged. That is, the alignment film AF1 can be formed by forming a polyimide film on the surface of the glass substrate GS1 on which the TFT array TFA is formed, and performing a “rubbing” process on the polyimide film. “Rubbing” means rubbing, and when the surface of the polyimide film is rubbed with a roll (brush) made of nylon or the like, fine scratches are formed on the rubbed portion. As a result, liquid crystal molecules are aligned in parallel along fine scratches formed on the surface of the polyimide film. Therefore, the alignment film AF1 is a film in which fine scratches are formed on the surface of the polyimide film by rubbing, and has a function of aligning the direction in which liquid crystal molecules are arranged. As described above, the TFT glass substrate TS is formed.

  Next, the configuration of the color filter glass substrate CS will be described. First, the alignment film AF2 is formed so as to be in contact with the liquid crystal LC. This alignment film AF2 is also formed of, for example, a polyimide film, and has a role of aligning the direction in which liquid crystal molecules are arranged. That is, the alignment film AF2 can be formed by forming a polyimide film on the surface of the color filter glass substrate CS in contact with the liquid crystal LC and subjecting the polyimide film to a “rubbing” process. “Rubbing” means rubbing, and when the surface of the polyimide film is rubbed with a roll (brush) made of nylon or the like, fine scratches are formed on the rubbed portion. As a result, liquid crystal molecules are aligned in parallel along fine scratches formed on the surface of the polyimide film. Therefore, the alignment film AF2 is a film in which fine scratches are formed on the surface of the polyimide film by rubbing, and has a function of aligning the direction in which liquid crystal molecules are arranged.

  Subsequently, an ITO electrode ITO2 is formed on the alignment film AF2. In order to drive the liquid crystal LC, it is necessary to apply a voltage above and below the liquid crystal LC, and to apply a voltage above and below the liquid crystal LC, it is also necessary to form electrodes on the color filter glass substrate CS. However, even if it says an electrode, if a normal metal electrode is formed, the normal metal electrode cannot transmit light. For this reason, it is necessary to form a transparent electrode with the substance which permeate | transmits light also in the color filter glass substrate CS which comprises liquid crystal display part DU. For this reason, the ITO electrode ITO2 is formed on the color filter glass substrate CS. That is, since the ITO electrode ITO2 is a transparent electrode that can transmit light, it is used in the liquid crystal display unit DU. The ITO electrode ITO2 is formed on the alignment film AF2 in contact with the liquid crystal LC by thinning indium and a small amount of tin oxide for reducing the resistance. In this way, the liquid crystal LC is sandwiched between the ITO electrode ITO1 formed on the TFT glass substrate TS and the ITO electrode ITO2 formed on the color filter glass substrate CS. As a result, it can be seen that a voltage can be applied above and below the liquid crystal LC, and the liquid crystal LC can be driven.

  Next, a color filter CF is formed on the ITO electrode ITO2. For example, the color filter CF can represent one color information with three pixels. Specifically, an arbitrary color can be displayed by applying a small filter corresponding to one of the three primary colors to each of the three pixels. For example, in order to display a certain color, the color is decomposed into three primary color components of red (R), green (G), and blue (B), and the brightness of each is displayed with black and white pixels. For black and white display, a red filter is applied to pixels corresponding to the red component, a green filter is applied to pixels corresponding to the green component, and a blue filter is applied to pixels corresponding to the blue component. As a result, the three primary colors are additively mixed to reproduce the original color. By providing the color filter CF in this way, it is possible to realize colorization of an image displayed on the liquid crystal display device LCD.

  A glass substrate GS2 is disposed on the color filter CF. The glass substrate GS2, like the glass substrate GS1, needs to ensure the display performance of the liquid crystal display device LCD. Therefore, unlike a general window glass, the surface is very smooth and there is no undulation on the surface. Is required. That is, the glass substrate GS2 is also composed of a glass substrate having a very high flatness. As described above, the color filter glass substrate CS is formed.

<Operation of liquid crystal display>
The liquid crystal display unit DU in the first embodiment is configured as described above, and the operation of the liquid crystal display unit DU will be described below with reference to the drawings. Specifically, in the first embodiment, an operation using a nematic liquid crystal will be described. A nematic liquid crystal is a liquid crystal in which long molecules are aligned in a certain direction, and this aligned direction is called a director.

  First, as shown in FIG. 2, a liquid crystal LC is inserted between the TFT glass substrate TS and the color filter glass substrate CS. Then, in the region in contact with the TFT glass substrate TS, the liquid crystal LC is arranged such that the liquid crystal molecules are lying in parallel with the TFT glass substrate TS. That is, the director of the liquid crystal LC is set parallel to the TFT glass substrate TS. On the other hand, in the color filter glass substrate CS, the liquid crystal molecules are also in a state of lying in parallel with the color filter glass substrate CS. At this time, the direction of the liquid crystal molecules lying on the TFT glass substrate TS and the direction of the liquid crystal molecules parallel to the color filter substrate CS under the color filter substrate CS are changed by 90 degrees. In this case, the direction of the liquid crystal molecules gradually twists from the TFT glass substrate TS to the color filter glass substrate CS, and the direction of the liquid crystal molecules in the region in contact with the TFT glass substrate TS and the color filter glass The liquid crystal molecules in the region in contact with the substrate CS are twisted by 90 degrees.

  Assuming the above-described configuration, as shown in FIG. 3, the polarizing plate PL1 and the polarizing plate PL2 are arranged so as to sandwich the liquid crystal LC, and the vibration direction (direction a) of light transmitted through the polarizing plate PL1 and the polarization The polarizing plate PL and the polarizing plate PL2 are arranged so that the vibration directions (b direction) of the light transmitted through the plate PL2 are orthogonal to each other. At this time, as shown in FIG. 3, the liquid crystal molecules are arranged on the surface of the polarizing plate PL1 so that the direction in which the liquid crystal molecules are aligned is the same as the vibration direction of the light passing through the polarizing plate PL1. . That is, the liquid crystal molecules are aligned in the same direction as the vibration direction of the light transmitted through the polarizing plate PL1. Similarly, the polarizing plate PL2 is also arranged so that the direction in which the liquid crystal molecules are aligned is parallel to the vibration direction of the light transmitted through the polarizing plate PL2. Here, since the polarizing directions of the polarizing plate PL1 and the polarizing plate PL2 are perpendicular to each other, the light incident on the polarizing plate PL1 from the backlight is polarized unless the liquid crystal LC is present. It is considered that the plate PL2 cannot be transmitted.

  However, the liquid crystal molecules constituting the liquid crystal LC sandwiched between the polarizing plate PL1 and the polarizing plate PL2 are transmitted between the polarizing plate PL1 and the polarizing plate PL2 through the polarizing plate PL2 from the vibration direction of the light passing through the polarizing plate PL1. The direction is gradually changed in the direction of vibration of light. In other words, the way liquid crystal molecules are arranged (the direction in which the liquid crystal molecules are aligned) changes by 90 degrees from the polarizing plate PL1 toward the polarizing plate PL2. As a result, when light enters the polarizing plate PL1 from the backlight, the light that has passed through the polarizing plate PL1 (polarized light) travels along a twisted arrangement of liquid crystal molecules, and the vibration direction of the light is changed by 90 degrees. To reach the polarizing plate PL2. At this time, the vibration direction of the light reaching the polarizing plate PL2 is changed to the same direction as the vibration direction of the light transmitted through the polarizing plate PL2 due to the twisted arrangement of the liquid crystal molecules, and thus transmits through the polarizing plate PL2. That is, the light incident on the polarizing plate PL1 from the backlight changes in the vibration direction by 90 degrees by the liquid crystal molecules, and as a result, can pass through the polarizing plate PL2.

  As described above, the property of changing the vibration direction of light in the liquid crystal LC is called “light application”. That is, in the nematic liquid crystal, light can be transmitted between the polarizing plates PL1 and PL2 orthogonal to each other by twisting the arrangement of the liquid crystal molecules. As described above, light can be transmitted when no voltage is applied to the liquid crystal LC. Therefore, it can be seen that in the liquid crystal display device according to the first embodiment, pixels are displayed in white when no voltage is applied to the liquid crystal LC.

  Next, consider a case where a voltage is applied to the upper and lower electrodes (ITO electrode ITO1 and ITO electrode ITO2 in FIG. 2) sandwiching the liquid crystal LC. In this case, as shown in FIG. 4, the liquid crystal molecules constituting the liquid crystal LC cancel the twisted arrangement, and stand upright vertically with respect to the polarizing plate PL1 and the polarizing plate PL2. As a result, the light application property of the liquid crystal molecules is lost, and the light that has passed through the polarizing plate PL1 reaches the polarizing plate PL2 without changing the vibration direction even if it passes through the liquid crystal LC. Here, the vibration direction of the light passing through the polarizing plate PL1 and the vibration direction of the light passing through the polarizing plate PL2 are orthogonal to each other, so that the polarizing plate does not change after passing through the polarizing plate PL1. The light that reaches PL2 cannot pass through the polarizing plate PL2. Therefore, it can be seen that the pixels in which voltage is applied to the upper and lower electrodes (ITO electrode ITO1 and ITO electrode ITO2 in FIG. 2) sandwiching the liquid crystal LC display black. As described above, when a voltage is not applied to the upper and lower electrodes (ITO electrode ITO1 and ITO electrode ITO2 in FIG. 2) sandwiching the liquid crystal LC, white display can be performed, while the upper and lower electrodes sandwiching the liquid crystal LC (FIG. 2). It can be seen that when a voltage is applied to the ITO electrodes ITO1 and ITO2), black display can be performed. As a result, any character or figure can be displayed on the screen by performing white display or black display for each pixel.

  As described above, when no voltage is applied to the upper and lower electrodes (ITO electrode ITO1 and ITO electrode ITO2 in FIG. 2) sandwiching the liquid crystal LC, the liquid crystal molecules are directed from the TFT glass substrate TS to the color filter glass substrate CS. It is necessary to gradually twist the direction. Specifically, the liquid crystal molecules are arranged so that the direction in which the liquid crystal molecules face in the region in contact with the TFT glass substrate TS and the direction in which the liquid crystal molecules face in the region in contact with the color filter glass substrate CS are twisted by 90 degrees. There is a need to. Realizing such an arrangement of liquid crystal molecules is important from the viewpoint of image display, but this arrangement of liquid crystal molecules can be realized by using an alignment film.

  Specifically, the alignment film AF1 shown in FIGS. 3 and 4 can be formed by forming a polyimide film on the surface of the TFT glass substrate TS and rubbing the polyimide film. Similarly, the alignment film AF2 shown in FIGS. 3 and 4 can be formed by forming a polyimide film on the surface of the color filter glass substrate CS and rubbing the polyimide film. Rubbing means rubbing, and when the surface of the polyimide film is rubbed with a roll (brush) made of nylon or the like, fine scratches are formed at the rubbed place. Thereby, the arrangement direction of the liquid crystal molecules is controlled by utilizing the property that the liquid crystal molecules are arranged in parallel along the fine scratches formed on the surface of the polyimide film. Therefore, for example, by changing the rubbing direction of the polyimide film formed on the TFT glass substrate TS and the rubbing direction of the polyimide film formed on the color filter glass substrate CS by exactly 90 degrees, the liquid crystal molecules The direction in which the lines are arranged can gradually change by 90 degrees between the TFT glass substrate TS and the color filter glass substrate CS. From the above, the roles of the alignment film AF1 and the alignment film AF2 are important, and the technical idea in the first embodiment relates to the manufacturing process of the alignment film AF1 and the alignment film AF2.

<Method for manufacturing liquid crystal display device>
Below, the manufacturing method of a liquid crystal display device is demonstrated, referring drawings. FIG. 5 is a flowchart showing a flow of manufacturing steps for manufacturing the liquid crystal display device. First, a TFT glass substrate and a color filter glass substrate shown in FIG. 5 are formed from a glass substrate.

  Specifically, a glass substrate is prepared, and a thin film transistor is formed on the glass substrate by repeatedly using a cleaning technique, a photolithography technique, an etching technique, and an ashing technique. Thereby, the TFT glass substrate which formed the thin-film transistor on the surface of the glass substrate can be obtained (S101). Subsequently, after a cleaning process is performed on the TFT glass substrate (S102), an alignment film made of, for example, a polyimide film is applied to the surface of the TFT glass substrate (S103). Thereafter, the surface of the TFT glass substrate on which the alignment film is formed is rubbed (S104). Thereby, an alignment film having fine scratches aligned in a predetermined direction can be formed on the surface of the TFT glass substrate. Then, after rubbing the TFT glass substrate, the surface of the TFT glass substrate is cleaned (S105). Thereafter, a sealing agent is applied to the surface of the TFT glass substrate (S106).

  On the other hand, after preparing a glass substrate and forming a black matrix on this glass substrate, a color filter is formed on the glass substrate by using a pigment dispersion method, a dyeing method, an electrodeposition method or a printing method. . Thereby, the color filter glass substrate which formed the color filter in the surface of a glass substrate can be obtained (S107). Subsequently, after the color filter glass substrate is washed (S108), an alignment film made of, for example, a polyimide film is applied to the surface of the color filter glass substrate (S109). Thereafter, the surface of the color filter glass substrate on which the alignment film is formed is rubbed (S110). Thereby, an alignment film having fine scratches aligned in a predetermined direction can be formed on the surface of the color filter glass substrate. Then, after rubbing the color filter glass substrate, the surface of the color filter glass substrate is washed (S111). Thereafter, a spacer is applied to the surface of the color filter glass substrate (S112).

  Next, after the TFT glass substrate coated with the sealant and the color filter glass substrate coated with the spacer are bonded together (S113), the TFT glass substrate bonded to the color filter glass substrate is scribed (divided). (S114). Thereby, the bonded TFT glass substrate and color filter glass substrate are cut to the size of each liquid crystal display device. Thereafter, liquid crystal is injected into the gap between the TFT glass substrate and the color filter glass substrate secured by the sealant and the spacer (S115). Then, the gap (space) into which the liquid crystal is injected is sealed (S116).

  Subsequently, after attaching a pair of polarizing plates so as to sandwich the bonded TFT glass substrate and color filter glass substrate (S117), an inspection is performed (S118). In this way, a liquid crystal panel can be manufactured. A drive circuit for driving the liquid crystal panel is pressure-bonded to the manufactured liquid crystal panel (S119), and then a backlight is mounted on the liquid crystal panel (S120). Next, the liquid crystal panel on which the backlight and the drive circuit are mounted is inspected (S121), and finally the liquid crystal display device is completed (S122).

  A liquid crystal display device can be manufactured as described above. In the first embodiment, in the manufacturing process of the liquid crystal display device described above, an alignment film application step (S103) for applying an alignment film on the surface of the TFT glass substrate or an alignment film for applying an alignment film on the surface of the color filter glass substrate. Attention is paid to the film application step (S109). That is, the technical idea in the first embodiment is implemented in the alignment film coating process (S103, S109). In the following, first, the current problems in the alignment film application step (S103, S109) will be described, and then the technical idea in the first embodiment, which has been devised to solve the problems, will be described.

<Current problems in alignment film coating process>
In a liquid crystal display device, in particular, a small-to-medium-sized liquid crystal display device, there is a demand to make the frame region of the glass substrate where the liquid crystal display portion is not formed as narrow as possible from the viewpoint of securing a display area as much as possible. Specifically, there is a demand for the width of the frame region to be about 1 mm, but in the current alignment film coating process, there is a limit to setting the width of the frame region to about 2 mm. Hereinafter, the current alignment film coating process will be described with reference to the drawings.

  First, the first current technology will be described. FIG. 6 is a schematic diagram showing the first current technology used in the alignment film coating process. This first current technology is a technology using a flexographic printing apparatus. As shown in FIG. 6, in the first current technology using a flexographic printing apparatus, a roller-shaped flexographic printing apparatus FP is placed on a glass substrate while, for example, ink INK containing polyimide is dropped on the flexographic printing apparatus FP having a roller shape. Roll over GS (TFT glass substrate or color filter glass substrate collectively referred to as glass substrate GS). As a result, the ink INK is deposited on the glass substrate GS, and the alignment film AF made of the ink INK is applied onto the glass substrate GS. In the first current technology, the flatness of the alignment film AF can be ensured even if there is a concavo-convex shape NF due to a through hole or a pattern step (for example, a formation pattern of a thin film transistor) formed in the glass substrate GS. it can. However, since the ink INK is dropped on the flexographic printing apparatus FP and the flexographic printing apparatus FP is rotated to apply the alignment film AF on the glass substrate GS, the material use efficiency of the ink INK as a material is poor. There is a point. Furthermore, an important problem is that it is necessary to secure a width L1 of the frame region of the glass substrate GS of about 2 mm from the rotational accuracy of the flexographic printing apparatus FP and the positional accuracy of the ink INK suspended from the flexographic printing apparatus FP. . That is, in the first current technology using the flexographic printing apparatus FP, there is a limit that the width of the frame region is about 2 mm, and there is a problem that the request to make the width of the frame region about 1 mm cannot be satisfied. As a result, it becomes difficult to manufacture a liquid crystal display device having a display area as large as possible.

  Next, the second current technology will be described. FIG. 7 is a schematic diagram showing the second current technology used in the alignment film coating step. This second current technology is a technology using an ink jet device under normal pressure (atmospheric pressure). As shown in FIG. 7, in the second current technology using the ink jet device under atmospheric pressure, the ink INK is ejected from the ejection holes HL of the ink jet head IJH toward the glass substrate GS, thereby aligning the glass substrate GS. A film AF is applied. In the second current technology, since the ink INK is ejected under atmospheric pressure, it takes some time for the ink INK applied to the glass substrate GS to dry. For this reason, the ink INK applied to the glass substrate GS is leveled (flattened) even if there is a concavo-convex shape NF due to a through hole or a pattern step (for example, a formation pattern of a thin film transistor) formed in the glass substrate GS. In addition, the flatness of the alignment film AF can be ensured. However, since the ink INK is ejected under atmospheric pressure, the ink INK ejected from the ejection hole HL is easily affected by the flow (fluctuation) caused by the atmosphere. In other words, since the ink INK from the ink jet head IJH tends to fluctuate due to the influence of the atmosphere, the width L1 of the frame region of the glass substrate GS needs to be secured to about 2 mm. In other words, even in the second state-of-the-art technology using an ink jet device under atmospheric pressure, the limit of the width of the frame region is about 2 mm, and the request to make the width of the frame region about 1 mm cannot be satisfied. There is. As a result, it becomes difficult to manufacture a liquid crystal display device having a display area as large as possible.

  Next, the third current technology will be described. FIG. 8 is a schematic diagram showing a third current technology used in the alignment film coating step. This third current technology is a technology using an ink jet device under reduced pressure (for example, 30 kpa). As shown in FIG. 8, in the third current technology using the ink jet device under reduced pressure, the ink INK is ejected from the ejection holes HL of the ink jet head IJH toward the glass substrate GS, whereby the alignment film is applied to the glass substrate GS. Apply AF. In the third current technology, since the ink INK is ejected under reduced pressure, the ink INK ejected from the ejection hole HL is less susceptible to the influence of air flow (fluctuation). That is, since the pressure is reduced, the influence of air is reduced, and variations in how the ink INK is ejected from the inkjet head IJH are less likely to occur. For this reason, the printing application accuracy can be improved, and the request for setting the width L2 of the frame region of the glass substrate GS to about 1 mm can be satisfied. However, in the third current technology, since the ink INK is ejected under reduced pressure, the quick drying property of the ink INK applied to the glass substrate GS is increased. Therefore, if there is a concavo-convex shape NF due to a through hole or a pattern step (for example, a thin film transistor formation pattern) formed in the glass substrate GS, the ink INK applied to the glass substrate GS is leveled before the ink INK is leveled. However, there is a problem that unevenness reflecting the uneven shape NF is formed on the surface of the alignment film AF. When unevenness is generated on the surface of the alignment film AF in this manner, it causes display unevenness in the liquid crystal display device, which causes a decrease in performance of the liquid crystal display device.

  From the above, in the first to third current technologies described above, it is possible to realize a print coating method that can apply the alignment film to the glass substrate with good flatness and can make the frame region as narrow as possible. You can see that it is not. Therefore, in the printing application method according to the first embodiment, the orientation film can be applied to the glass substrate with good flatness and the frame area can be made as narrow as possible. Below, the printing application method in this Embodiment 1 which gave this device is demonstrated.

<Print coating apparatus in the first embodiment>
First, the configuration of an ink jet coating apparatus (print coating apparatus) IJA used in the print coating method according to the first embodiment will be described. FIG. 9 is a diagram illustrating a configuration of the inkjet coating apparatus IJA according to the first embodiment. As shown in FIG. 9, the ink jet coating apparatus IJA according to the first embodiment has a chamber (housing) CB, and a stage ST and an ink jet head IJH are arranged in the chamber CB. The stage ST is configured so that a substrate can be arranged, and the stage ST can move in the horizontal direction with the substrate arranged. On the other hand, an ink jet head IJH is disposed above the stage ST, and ink is ejected from the ink jet head IJH, and an alignment film made of ink is applied (printed) to the substrate disposed on the stage ST. It is configured to be able to. The inside of the chamber CB in which the stage ST and the ink jet head IJH are arranged can be reduced in pressure by about 30 kpa by a vacuum pump or the like, and can be maintained at an atmospheric pressure (normal pressure) state. It is configured. That is, the ink jet coating apparatus IJA according to the first embodiment is configured to be able to operate both under reduced pressure of about 30 kpa and under atmospheric pressure (normal pressure).

<Print coating method in the first embodiment>
The ink jet coating apparatus IJA according to the first embodiment is configured as described above, and the operation thereof will be described below. By describing the operation of the inkjet coating apparatus IJA, the printing coating method in the first embodiment will be described.

  FIG. 10 is a flowchart for explaining the operation of the inkjet coating apparatus IJA according to the first embodiment. The operation of the inkjet coating apparatus IJA according to the first embodiment will be described with reference to the flowchart shown in FIG.

  First, a glass substrate is placed on a stage ST provided in the inkjet coating apparatus IJA (S201). The glass substrate is, for example, a TFT glass substrate on which a thin film transistor is formed, or a color filter glass substrate on which a color filter is formed. Therefore, through-holes and pattern steps (for example, steps due to thin film transistor patterns) exist on the surface of the glass substrate, and an uneven shape is formed.

  Subsequently, the pressure in the chamber CB is reduced. Specifically, for example, the pressure in the chamber CB is reduced to about 30 kpa by a vacuum pump or the like (S202). Note that the glass substrate may be disposed on the stage ST provided in the ink jet coating apparatus IJA after the pressure in the chamber CB is first reduced. Thereafter, ink is applied only to the outer peripheral portion of the glass substrate disposed on the stage ST while maintaining the inside of the chamber CB under reduced pressure (S203). For example, the ink is applied only to the outer peripheral portion of the glass substrate by controlling the ink ejected from the ejection holes of the inkjet head IJH. Thereby, the alignment film is applied (printed) only on the outer peripheral portion of the glass substrate.

  Next, for example, by opening the chamber CB, the pressure in the chamber CB is made normal (atmospheric) (S204). Then, ink is applied to the inner peripheral portion of the glass substrate disposed on the stage ST in a state where the pressure in the chamber CB is maintained under normal pressure (under atmospheric pressure) (S205). For example, the inner peripheral portion ink of the glass substrate is applied by controlling the ink ejected from the ejection holes of the inkjet head IJH. Thereby, the alignment film is applied (printed) not only on the outer peripheral portion of the glass substrate but also on the inner peripheral portion which is the inner region of the outer peripheral portion. As described above, the alignment film can be applied on the glass substrate.

  Hereinafter, the printing application method according to the first embodiment will be described in more detail with reference to FIG. First, after placing a glass substrate on a stage provided in an inkjet coating apparatus, the pressure in the chamber is reduced. Specifically, for example, the pressure in the chamber is reduced to about 30 kpa by a vacuum pump or the like. Then, as shown in the left diagram of FIG. 11, the ink INK is applied only to the outer peripheral portion of the glass substrate GS disposed on the stage while maintaining the inside of the chamber under reduced pressure. For example, the ink INK is applied (printed) only to the outer peripheral portion of the glass substrate GS by controlling the ejection of the ink INK from the inkjet head IJH. At this time, since the ink INK is ejected from the ejection holes HL of the inkjet head IJH in a reduced pressure state, the ink INK ejected from the ejection holes HL is less affected by the flow (fluctuation) due to air. That is, since the pressure is reduced, the influence of air is reduced, and variations in how the ink INK is ejected from the inkjet head IJH are less likely to occur. For this reason, the printing application accuracy can be improved, and the width L2 of the frame region of the glass substrate GS can be narrowed (about 1 mm). That is, the first embodiment is characterized in that, in a reduced pressure state, the ink INK is ejected from the ejection holes HL of the inkjet head IJH, and the alignment film AF made of the ink INK is formed on the outer peripheral portion of the glass substrate GS. is there. As a result, first, since the ink INK is ejected from the ink jet head IJH, the ink INK is less affected by the air flow (fluctuation), so that the ink INK can be printed on the outer peripheral portion of the glass substrate GS with high positional accuracy. it can. Second, since the ink INK applied to the glass substrate GS is placed in a reduced pressure state, the ink INK has a high quick drying property and is dried immediately after being applied to the glass substrate GS. For this reason, since the ink INK is solidified without moving after being applied to the glass substrate GS, it is possible to suppress deviation from the set application position. As described above, according to the first embodiment, by ejecting the ink INK from the inkjet head IJH under reduced pressure, the first advantage that it is less affected by the air flow (fluctuation) and the quick drying property are high. The alignment film AF can be applied to the outer peripheral portion of the glass substrate GS with high accuracy by the second advantage that the position is not easily displaced since it is dried immediately after being applied to the glass substrate GS. As a result, according to the first embodiment, the width L2 (for example, about 1 mm) of the frame region that is outside the outer peripheral portion of the glass substrate GS can be made extremely narrow.

  Subsequently, after the pressure in the chamber is restored to atmospheric pressure (normal pressure), as shown in the right diagram of FIG. 11, the glass substrate disposed on the stage with the chamber maintained at atmospheric pressure. Ink INK is applied to the inner peripheral portion that is the inner region of the outer peripheral portion of GS. For example, the ink INK is applied (printed) to the inner peripheral portion of the glass substrate GS by controlling the ejection of the ink INK from the inkjet head IJH. At this time, since the ink INK is ejected from the ejection holes HL of the inkjet head IJH in the atmospheric pressure state, the ink INK ejected from the ejection holes HL is easily affected by the flow (fluctuation) due to air. Since the alignment film AF applied under reduced pressure is formed on the outer peripheral portion of the glass substrate GS, the alignment film AF formed on the outer peripheral portion functions as, for example, a bank BK, and ink applied to the inner peripheral portion. It is possible to prevent INK from leaking outside the outer peripheral portion. That is, since the alignment film AF already formed on the outer peripheral portion can prevent the ink INK applied to the inner peripheral portion from protruding outside the outer peripheral portion, the alignment film AF is formed outside the outer peripheral portion of the glass substrate GS. The positional accuracy of the boundary region between the frame region and the region where the alignment film AF is formed is defined by the alignment film AF formed on the outer peripheral portion under reduced pressure. As a result, the outer boundary of the alignment film AF is positioned with high accuracy, so that the frame area can be narrowed.

  On the other hand, when the ink INK is applied to the inner peripheral portion that is the inner region of the outer peripheral portion of the glass substrate GS disposed on the stage while the chamber is maintained at atmospheric pressure, the ink INK is applied to the glass substrate GS. It takes more time for the ink INK to dry than in the reduced pressure state. For this reason, the ink INK applied to the glass substrate GS is leveled (flattened) even if there is a concavo-convex shape NF due to a through hole or a pattern step (for example, a formation pattern of a thin film transistor) formed in the glass substrate GS. Thus, the flatness of the alignment film AF can be ensured.

  As described above, in the first embodiment, first, the outer peripheral portion of the glass substrate GS is accurately formed by ejecting the ink INK to the outer peripheral portion of the glass substrate GS by the inkjet head IJH to form the alignment film AF in a reduced pressure state. An alignment film AF can be formed. Therefore, according to the printing application method in the first embodiment, the positional accuracy of the alignment film AF formed on the outer peripheral portion can be improved, so that the width L2 of the frame region can be reduced. As a result, the display area of the liquid crystal display device can be increased.

  On the other hand, in the inner peripheral portion that is the inner region of the outer peripheral portion of the glass substrate GS, the ink INK can be applied to the inner peripheral portion while maintaining the inside of the chamber under atmospheric pressure. Therefore, since the quick drying property is lower than that in the reduced pressure state and it is difficult to dry, the liquid state of the ink INK can be lengthened, and the unevenness of the glass substrate GS can be absorbed to improve the flatness of the surface of the alignment film AF. be able to. In other words, by applying (printing) the ink INK under atmospheric pressure, the leveling (flattening) function of the liquefied ink INK can be sufficiently exerted, so that the inner peripheral portion of the glass substrate GS where unevenness exists. Flatness on the surface of the alignment film AF formed on the surface can be improved. Therefore, according to the printing application method in the first embodiment, the frame region of the glass substrate GS can be made as narrow as possible, and the flatness of the alignment film AF formed on the glass substrate GS can be improved. Thus, it is possible to obtain a remarkable effect that cannot be realized by the conventional technology. As a result, according to the first embodiment, since the frame area can be made as narrow as possible, the display area of the liquid crystal display device can be increased. Further, since the flatness of the alignment film AF formed on the glass substrate GS can be improved, display unevenness due to the unevenness of the surface of the alignment film AF can be suppressed, and the performance of the liquid crystal display device can be improved. be able to.

  The technical idea in the first embodiment is that the first feature point that the alignment film AF can be formed with high positional accuracy, which is an advantage of the printing coating method of ejecting the ink INK from the ink jet head IJH under reduced pressure, and the ink jet under the atmospheric pressure. The second characteristic point that can improve the flatness of the alignment film AF regardless of the unevenness of the glass substrate GS, which is an advantage of the printing application method of ejecting the ink INK from the head IJH, is to be maximized. There are features. That is, in the first embodiment, in consideration of the first feature point described above, focusing on the fact that the frame region can be made as narrow as possible if the alignment film AF can be formed only on the outer peripheral portion of the glass substrate GS with high positional accuracy, and In consideration of the second feature point described above, focusing on the point that the leveling function should be sufficiently exerted only on the inner peripheral portion of the uneven glass substrate GS, the printing application method according to the first embodiment is realized. It is what.

  In other words, the disadvantage of the ink-jet coating method under reduced pressure is that the ink INK has a high quick drying property, and that the alignment film AF is formed reflecting the unevenness of the glass substrate GS. In the case where the alignment film AF is formed only on the outer peripheral portion of the substrate, attention is paid to the point that the disadvantage of the ink jet coating method under reduced pressure does not become obvious. The demerit of the ink jet coating method under atmospheric pressure is that the position accuracy of the ink INK to be applied is accurately grasped, not the outer periphery of the glass substrate GS that is the boundary region with the frame region, but the inner periphery. In the case where the alignment film AF is formed only on the portion, attention is paid to the point that the disadvantage of the ink jet coating method under atmospheric pressure does not become obvious.

  As a result, the printing application method according to the first embodiment sufficiently exhibits the merit of the ink jet coating method under reduced pressure and the merit of the ink jet coating method under atmospheric pressure, and the ink jet coating method under reduced pressure. This is an excellent technical idea that is configured so that the disadvantages of the inkjet coating method under atmospheric pressure do not become obvious.

<Effect in the first embodiment>
The effects in the first embodiment are summarized as follows.

  (1) The alignment film AF can be accurately formed on the outer peripheral portion of the glass substrate GS by ejecting the ink INK to the outer peripheral portion of the glass substrate GS by the inkjet head IJH in a reduced pressure state to form the alignment film AF. it can. Therefore, according to the printing application method in the first embodiment, the positional accuracy of the alignment film AF formed on the outer peripheral portion can be improved, so that the width L2 of the frame region can be reduced. As a result, the display area of the liquid crystal display device can be increased.

  (2) In the inner peripheral portion that is the inner region of the outer peripheral portion of the glass substrate GS, the ink INK can be applied to the inner peripheral portion while maintaining the inside of the chamber under atmospheric pressure. Therefore, since the quick drying property is lower than that in the reduced pressure state and it is difficult to dry, the liquid state of the ink INK can be lengthened, and the unevenness of the glass substrate GS can be absorbed to improve the flatness of the surface of the alignment film AF. be able to. In other words, by applying (printing) the ink INK under atmospheric pressure, the leveling (flattening) function of the liquefied ink INK can be sufficiently exerted, so that the inner peripheral portion of the glass substrate GS where unevenness exists. Flatness on the surface of the alignment film AF formed on the surface can be improved.

  (3) According to the printing application method in the first embodiment, the above-described effects (1) and (2) can be obtained simultaneously. That is, according to the printing application method in the first embodiment, the frame region of the glass substrate GS can be made as narrow as possible, and the flatness of the alignment film AF formed on the glass substrate GS can be improved. The remarkable effect which cannot be realized by the conventional technology can be obtained.

  (4) Furthermore, according to the first embodiment, when the ink INK is ejected to the outer peripheral portion of the glass substrate GS by the inkjet head IJH in a decompressed state, the inner periphery is maintained in a state where the chamber is maintained at atmospheric pressure. The same type of ink INK can be used in both cases where the ink INK is applied to the portion. Therefore, since it is not necessary to use a plurality of types of inks INK, the cost of the liquid crystal display device can be reduced.

  For example, Embodiment 1 is a technical idea that pays attention to the fact that the drying properties of the ink INK itself can be made different when the same type of ink INK is used in a reduced pressure state and a normal pressure state. According to this technical idea, since the ink INK to be used can be made one type, a remarkable effect that the cost of the liquid crystal display device can be reduced can be obtained. On the other hand, for example, a technique that uses a plurality of types of inks having different drying properties while keeping the pressure constant may be considered. That is, it is also conceivable to form an alignment film on the outer peripheral portion of the glass substrate using an ink having a high quick drying property, and then forming an alignment film on the inner peripheral portion of the glass substrate using an ink having a low quick drying property. . However, this technique requires a plurality of types of inks having different properties, which increases the cost of the liquid crystal display device. Therefore, the technical idea in the first embodiment in which the drying property of the ink INK itself is made different by using the same type of ink INK in the reduced pressure state and the normal pressure state is to reduce the width of the frame region, and It can be said that this is an excellent technical idea from the viewpoint that the performance of the liquid crystal display device can be improved and the cost of the liquid crystal display device can be reduced.

  (5) In addition, the glass substrate GS used in the first embodiment may be a TFT glass substrate or a color filter glass substrate, but has a remarkable effect particularly when used for a TFT glass substrate. Obtainable. This is because thin film transistors and through holes are formed on the TFT glass substrate, and the surface unevenness tends to be larger than that of the color filter glass substrate. In other words, even with a TFT glass substrate having such a large uneven shape, the alignment film AF having high flatness can be formed on the TFT glass substrate by applying the printing application method according to the first embodiment.

<Modification of Embodiment 1>
Next, a first modification of the first embodiment will be described. FIG. 12 is a diagram illustrating a printing application method according to the first modification. Also in the first modification, first, after placing the glass substrate on the stage provided in the inkjet coating apparatus, the pressure in the chamber is reduced. Specifically, for example, the pressure in the chamber is reduced to about 30 kpa by a vacuum pump or the like. Then, as shown in the left diagram of FIG. 12, the ink INK is extended along the outer peripheral portion of the glass substrate GS arranged on the stage and the center line extending in the vertical direction while maintaining the inside of the chamber under reduced pressure. Apply. For example, by controlling the ejection of the ink INK from the inkjet head IJH, the ink INK is applied (printed) along the outer peripheral portion of the glass substrate GS and the center line extending in the vertical direction. Thereby, the bank BK1 made of the alignment film AF can be formed on the outer peripheral portion of the glass substrate GS, and the bank BK2 made of the alignment film AF can be formed on the center line extending in the vertical direction of the glass substrate GS. it can. At this time, since the ink INK is ejected from the ejection holes HL of the inkjet head IJH in a reduced pressure state, the ink INK ejected from the ejection holes HL is less affected by the flow (fluctuation) due to air. That is, since the pressure is reduced, the influence of air is reduced, and variations in how the ink INK is ejected from the inkjet head IJH are less likely to occur. For this reason, the printing application accuracy can be improved, and the width L2 of the frame region of the glass substrate GS can be narrowed (about 1 mm).

  Subsequently, after the pressure in the chamber is restored to atmospheric pressure (normal pressure), as shown in the right diagram of FIG. 12, the glass substrate disposed on the stage with the chamber maintained at atmospheric pressure. Ink INK is applied to the inner peripheral portion divided by the outer peripheral portion (bank BK1) of GS and the center line (bank BK2) extending in the vertical direction. For example, the ink INK is applied (printed) to the inner peripheral portion of the glass substrate GS by controlling the ejection of the ink INK from the inkjet head IJH. At this time, since the ink INK is ejected from the ejection holes HL of the inkjet head IJH in the atmospheric pressure state, the ink INK ejected from the ejection holes HL is easily affected by the flow (fluctuation) due to air. Since the alignment film AF applied under reduced pressure is formed on the outer peripheral portion of the glass substrate GS, the alignment film AF formed on the outer peripheral portion functions as, for example, a bank, and the ink INK applied on the inner peripheral portion. Can be prevented from leaking to the outside of the outer periphery.

  Here, in the first modification, as shown in the left diagram of FIG. 12, the bank BK1 and the bank BK2 are formed on the glass substrate GS. In particular, the inner peripheral portion of the glass substrate GS is divided by the bank BK2. Yes. That is, the inner peripheral portion of the glass substrate GS is divided into two small areas (divided into two) by the bank BK2. As a result, according to the first modification, when the ink INK is applied to the inner peripheral portion of the glass substrate GS disposed on the stage while the chamber is maintained at atmospheric pressure, the ink INK is divided by the bank BK2. Ink INK is applied to each small area. Therefore, according to the first modification, there is an advantage that the liquid ink INK can be easily leveled (flattened).

  Then, the modification 2 of this Embodiment 1 is demonstrated. FIG. 13 is a diagram illustrating a printing application method according to the second modification. Also in the second modification, first, after placing the glass substrate on the stage provided in the ink jet coating apparatus, the pressure in the chamber is reduced. Specifically, for example, the pressure in the chamber is reduced to about 30 kpa by a vacuum pump or the like. Then, as shown in the left diagram of FIG. 13, with the inside of the chamber kept under reduced pressure, the outer periphery of the glass substrate GS arranged on the stage, the center line extending in the vertical direction, and the horizontal direction are extended. The ink INK is applied along the existing center line. For example, by controlling the ejection of the ink INK from the inkjet head IJH, the ink INK is applied (printed) along the outer peripheral portion of the glass substrate GS, the center line extending in the vertical direction, and the center line extending in the horizontal direction. ) Thereby, the bank BK1 made of the alignment film AF can be formed on the outer peripheral portion of the glass substrate GS, and the bank BK2 made of the alignment film AF can be formed on the center line extending in the vertical direction of the glass substrate GS. it can. Further, the bank BK3 made of the alignment film AF can be formed on the center line extending in the lateral direction of the glass substrate GS. At this time, since the ink INK is ejected from the ejection holes HL of the inkjet head IJH in a reduced pressure state, the ink INK ejected from the ejection holes HL is less affected by the flow (fluctuation) due to air. That is, since the pressure is reduced, the influence of air is reduced, and variations in how the ink INK is ejected from the inkjet head IJH are less likely to occur. For this reason, the printing application accuracy can be improved, and the width L2 of the frame region of the glass substrate GS can be narrowed (about 1 mm).

  Subsequently, after the pressure in the chamber is restored to atmospheric pressure (normal pressure), as shown in the right diagram of FIG. 12, the glass substrate disposed on the stage with the chamber maintained at atmospheric pressure. The ink INK is applied to the inner peripheral portion divided by the outer peripheral portion (bank BK1) of the GS, the center line (bank BK2) extending in the vertical direction, and the center line (bank BK3) extending in the horizontal direction. For example, the ink INK is applied (printed) to the inner peripheral portion of the glass substrate GS by controlling the ejection of the ink INK from the inkjet head IJH. At this time, since the ink INK is ejected from the ejection holes HL of the inkjet head IJH in the atmospheric pressure state, the ink INK ejected from the ejection holes HL is easily affected by the flow (fluctuation) due to air. Since the alignment film AF applied under reduced pressure is formed on the outer peripheral portion of the glass substrate GS, the alignment film AF formed on the outer peripheral portion functions as, for example, a bank, and the ink INK applied on the inner peripheral portion. Can be prevented from leaking to the outside of the outer periphery.

  Here, in the second modification, as shown in the left diagram of FIG. 13, the bank BK1, the bank BK2, and the bank BK3 are formed on the glass substrate GS. In particular, the inner periphery of the glass substrate GS is the bank BK2. It is delimited by the bank BK3. That is, the inner peripheral portion of the glass substrate GS is divided into small areas (four divisions) by the banks BK2 and BK3. As a result, according to the second modification, when the ink INK is applied to the inner periphery of the glass substrate GS disposed on the stage while the chamber is maintained at atmospheric pressure, the banks BK2 and BK3 are applied. Ink INK is applied to each of the small areas separated by. For this reason, according to the second modification, the liquid ink INK can be easily leveled (flattened).

  Considering Modification 1 and Modification 2 described above, the technical idea of the present invention is that the first region of the glass substrate GS disposed on the stage while maintaining the inside of the chamber under reduced pressure. A step of applying the ink INK along (for example, the outer peripheral portion, the center line extending in the vertical direction and the center line extending in the horizontal direction). After that, in a state where the inside of the chamber is maintained under atmospheric pressure, a second region (for example, the outer peripheral portion (bank BK1) of the glass substrate GS disposed on the stage and a center line (bank) extending in the vertical direction. A step of applying ink INK to BK2) and a center line (inner peripheral part divided by bank BK3) extending in the lateral direction. At this time, the first region is defined as a boundary line (boundary region) between the frame region and the outer peripheral portion, and a line (region) dividing the inner peripheral portion, and the second region is a region within the divided inner peripheral portion. It is prescribed. Therefore, for example, it can be said that the area of the first region is smaller than the area of the second region.

(Embodiment 2)
In the first embodiment, by using the same ink jet coating apparatus, the first ink is applied along the outer peripheral portion of the glass substrate disposed on the stage while the chamber is maintained under reduced pressure. An example has been described in which the process and the second process of applying ink to the inner periphery of the glass substrate GS arranged on the stage in a state where the inside of the chamber is maintained at atmospheric pressure are described. In the second embodiment, an example will be described in which the inkjet coating apparatus that performs the first step and the inkjet coating apparatus that performs the second step are different devices.

  In the second embodiment, the inkjet coating apparatus (first inkjet coating apparatus) that performs the first step and the inkjet coating apparatus (second inkjet coating apparatus) that performs the second process are different apparatuses, respectively. The inkjet coating apparatus has the same configuration as that of the inkjet coating apparatus IJA shown in FIG. 9 described in the first embodiment.

  Hereinafter, the printing application method according to the second embodiment will be described with reference to FIG. FIG. 14 is a flowchart for explaining the printing application method according to the second embodiment. As shown in FIG. 14, first, a glass substrate is placed on the first stage provided in the first chamber of the first inkjet coating apparatus (S301). The glass substrate is, for example, a TFT glass substrate on which a thin film transistor is formed, or a color filter glass substrate on which a color filter is formed. Therefore, through-holes and pattern steps (for example, steps due to thin film transistor patterns) exist on the surface of the glass substrate, and an uneven shape is formed.

  Subsequently, the pressure in the first chamber is reduced. Specifically, for example, the pressure in the first chamber is reduced to about 30 kpa by a vacuum pump or the like (S302). Thereafter, the ink is applied only to the outer peripheral portion of the glass substrate disposed on the first stage while the first chamber is maintained under reduced pressure (S303). For example, the ink is applied only to the outer peripheral portion of the glass substrate by controlling the ink ejected from the ejection holes of the inkjet head. Thereby, the alignment film is applied (printed) only on the outer peripheral portion of the glass substrate.

  Next, the glass substrate is unloaded from the first chamber of the first inkjet coating apparatus (S304). Then, the unloaded glass substrate is loaded into the second chamber of the second inkjet coating apparatus under normal pressure (S305). Subsequently, a glass substrate is disposed on the second stage in the second chamber (S306). Thereafter, in a state where the pressure in the second chamber is maintained under normal pressure (under atmospheric pressure), ink is applied to the inner peripheral portion of the glass substrate disposed on the second stage (S307). For example, the inner periphery ink of the glass substrate is applied by controlling the ink ejected from the ejection holes of the inkjet head. Thereby, the alignment film is applied (printed) not only on the outer peripheral portion of the glass substrate but also on the inner peripheral portion which is the inner region of the outer peripheral portion. As described above, the alignment film can be applied on the glass substrate.

  Also in the second embodiment, the same effect as in the first embodiment can be obtained.

  (1) For example, the alignment film can be accurately formed on the outer peripheral portion of the glass substrate by ejecting ink to the outer peripheral portion of the glass substrate with an ink jet head under reduced pressure to form the alignment film. Therefore, according to the printing application method in the second embodiment, the positional accuracy of the alignment film formed on the outer peripheral portion can be improved, so that the width of the frame region can be reduced. As a result, the display area of the liquid crystal display device can be increased.

  (2) In the inner peripheral portion, which is an inner region of the outer peripheral portion of the glass substrate, ink can be applied to the inner peripheral portion while the chamber is maintained at atmospheric pressure. Accordingly, since the quick drying property can be made lower than the reduced pressure state and difficult to dry, the liquid state of the ink can be lengthened, the unevenness of the glass substrate can be absorbed, and the flatness of the surface of the alignment film can be improved. . In other words, by applying (printing) the ink under atmospheric pressure, the leveling (flattening) function of the liquefied ink can be sufficiently exerted, so that it is formed on the inner peripheral portion of the glass substrate where there are irregularities. It is possible to improve the flatness on the surface of the alignment film.

  (3) According to the printing application method in the second embodiment, the effects (1) and (2) described above can be obtained simultaneously. That is, according to the printing application method in the second embodiment, the frame area of the glass substrate can be made as narrow as possible, and the flatness of the alignment film formed on the glass substrate can be improved. In this way, a remarkable effect that cannot be realized can be obtained.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  In the embodiment described above, an example in which an alignment film is applied to a glass substrate has been described as an example of a printing application method for printing a film on a substrate using an inkjet application apparatus. However, the technical idea of the present invention is The present invention is not limited to this, and can be widely applied to a printing coating method in which a film is printed on a substrate using an inkjet coating apparatus.

  The present invention can be widely used in the manufacturing industry using a printing coating technique for printing a film on a substrate using an inkjet coating apparatus.

AF alignment film AF1 alignment film AF2 alignment film BK bank BK1 bank BK2 bank BK3 bank BL backlight CHP semiconductor chip CF color filter CB chamber CS color filter glass substrate DU liquid crystal display unit FP flexo printing device FS flexible substrate GS glass substrate G GS2 glass substrate HL injection hole IJA inkjet coating device IJH inkjet head INK ink ITO1 ITO electrode ITO2 ITO electrode LC liquid crystal LCD liquid crystal display device NF uneven shape PL1 polarizing plate PL2 polarizing plate TFA TFT array TFT thin film transistor TS TFT glass substrate

Claims (10)

By using the inkjet head in a print coating apparatus comprising a chamber, a stage provided in the chamber, a substrate disposed on the stage, and an inkjet head provided in the chamber, A printing application method of applying an ink on a substrate and printing a film on the substrate,
(A) placing the substrate on the stage;
(B) setting the pressure in the chamber to a reduced pressure lower than atmospheric pressure;
(C) After the step (b), using the inkjet head, applying the ink to the outer periphery of the substrate;
(D) after the step (c), the step of setting the pressure in the chamber to atmospheric pressure;
(E) After the step (d), the ink of the same type as the ink used in the step (c) is applied to the inner peripheral portion, which is the inner region of the outer peripheral portion of the substrate, using the inkjet head. And a step of applying the coating. The printing application method according to claim 1,
The printing application method, wherein the inkjet head used in the step (c) and the inkjet head used in the step (e) are the same inkjet head. The printing application method according to claim 1,
The printing application method, wherein the substrate is a glass substrate. A printing application method according to claim 3,
The printing coating method, wherein the film is an alignment film used in a liquid crystal display device. The printing application method according to claim 4,
The printing application method, wherein the substrate is a glass substrate on which a thin film transistor is formed. The printing application method according to claim 4,
The printing application method, wherein the substrate is a glass substrate on which a color filter is formed. A first stage, a first stage provided in the first chamber, a first inkjet head provided in the first chamber, a second chamber, and a second stage provided in the second chamber. A printing and coating apparatus comprising a stage and a second inkjet head provided in the second chamber, wherein the first inkjet head and the second inkjet head are used to apply ink onto a substrate and A printing application method for printing a film on a substrate,
(A) disposing the substrate on the first stage provided in the first chamber;
(B) bringing the pressure inside the first chamber into a reduced pressure state lower than atmospheric pressure;
(C) After the step (b), using the first inkjet head provided in the first chamber, applying the ink to the outer peripheral portion of the substrate;
(D) after the step (c), carrying out the substrate coated with the ink on the outer peripheral portion from the first chamber;
(E) after the step (d), placing the substrate on the second stage provided in a second chamber having an internal pressure at atmospheric pressure;
(F) After the step (e), by using the second inkjet head provided in the second chamber, the ink is applied to an inner peripheral portion that is an inner region of the outer peripheral portion of the substrate. Comprising the steps of:
In the step (c), the ink applied to the outer peripheral portion of the substrate and the ink applied to the inner peripheral portion of the substrate in the step (f) are the same type of ink. The printing application method characterized by the above-mentioned. By using the inkjet head in a print coating apparatus comprising a chamber, a stage provided in the chamber, a substrate disposed on the stage, and an inkjet head provided in the chamber, A printing application method of applying an ink on a substrate and printing a film on the substrate,
(A) placing the substrate on the stage;
(B) setting the pressure in the chamber to a reduced pressure lower than atmospheric pressure;
(C) After the step (b), using the inkjet head, applying the ink to the first region of the substrate;
(D) after the step (c), the step of setting the pressure in the chamber to atmospheric pressure;
(E) After the step (d), the ink of the same type as the ink used in the step (c) is applied to the second region different from the first region of the substrate using the inkjet head. A printing application method comprising the steps of: A printing application method according to claim 8,
The area of the said 1st area | region is smaller than the area of the said 2nd area | region, The printing application | coating method characterized by the above-mentioned. A printing application method according to claim 9, wherein
The printing application method, wherein the first region is an outer peripheral portion of the substrate, and the second region is an inner peripheral portion of an inner region from the outer peripheral portion of the substrate.

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