JP2006189550A - Method for drawing matrix-shaped microregion by using ink jet process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a drawing method capable of suppressing the periodic variation in film thickness when matrix-shaped microregions are drawn by using an ink jet process. <P>SOLUTION: The drawing of pixels is performed onto a glass substrate 10 in which a black matrix 11 having surface water repellency is formed by using an ink jet device. A nozzle head 20 performs the discharge of ink to the glass substrate 10 from the horizontal direction (main scanning direction) to draw the pixels, and the ink is discharged by using the nozzle suspended on the black matrix 11, thereby connecting the pixels adjacent to each other in the longitudinal direction (sub-scanning direction) at random. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for drawing a matrix-like minute region using an inkjet method, and more particularly to a method for manufacturing a color filter used for a liquid crystal display element or the like.

  A color filter used in a liquid crystal display element or the like is generally manufactured using a photolithography method. In a color filter manufacturing method using a photolithography method, a pixel material pattern of each color is formed by patterning a resist material in which a pigment is dispersed using a photolithography method.

  In a color filter manufacturing method using a photolithographic method, pixel patterns of each color of R (red), G (green), and B (blue) are formed by a complicated process such as application of resist material, exposure, and development. Therefore, it is necessary to repeat three times, and the manufacturing process increases. Furthermore, there is a problem that the utilization efficiency of the resist material is poor. For this reason, the color filter manufacturing method using the photolithography method has a problem of high cost.

  In addition, as another method for producing a color filter, a method using an ink jet method has been studied. In the color filter manufacturing method using the ink jet method, a color filter can be manufactured by dropping a required amount of ink on a required place of the filter substrate, so that the color filter can be manufactured at low cost.

  However, in the ink jet method, there is a variation in the ink discharge amount for each nozzle. Therefore, when a color filter is manufactured using the ink jet method, the nozzle discharge variation causes a variation in the film thickness of the picture element. In addition, since these film thickness variations periodically exist due to the ejection mechanism of the ink jet method, such periodic film thickness variations are recognized as unevenness in the formed color filter. This will be described with reference to FIG.

  In the case of manufacturing a color filter using an inkjet method, a picture element is formed by ejecting ink while scanning a nozzle head 101 having a plurality of nozzles in a drawing direction (main scanning direction). Further, in the sub-scanning direction, the nozzle head 101 is moved relative to the filter substrate by the width of the nozzle head, and scanning in the drawing direction is performed again, and such scanning is repeated. The color filter picture elements are drawn.

  When drawing the color filter picture elements by such a method, the picture elements belonging to the same column in the main scanning direction are drawn by ink ejected from the same nozzle. For this reason, the variation in the film thickness occurs in the picture elements in each row due to the variation in the ink discharge amount at the nozzles. This variation in film thickness occurs periodically in the sub-scanning direction. In FIG. 7, the difference in the type of hatching of each picture element represents the difference in film thickness.

  In order to correct these film thickness variations, Patent Document 1 discloses a method of averaging discharge variations between nozzles by drawing within one picture element using a plurality of nozzles. Patent Document 2 discloses a method of measuring the discharge amount for each nozzle and drawing the optimum discharge amount for each pixel when drawing a single pixel using a plurality of nozzles. .

Furthermore, Patent Document 3 discloses a method of suppressing variations in film thickness by performing drawing using a plurality of nozzles on one picture element from the lateral direction of the picture element.
JP 10-151755 A (publication date: June 9, 1998) Japanese Patent Laid-Open No. 10-151773 (publication date: June 9, 1998) Japanese Patent Laid-Open No. 9-101212 (Publication Date: April 15, 1997)

  However, in the methods disclosed in Patent Documents 1 and 2, since the same picture element needs to be drawn a plurality of times, the number of drawing increases as compared with normal drawing, and the productivity cannot be obtained sufficiently. There is. In addition, with the method disclosed in Patent Document 2, it is difficult to accurately measure a subtle difference in the appropriate amount of liquid for each nozzle, and the measurement is very time-consuming. It's not possible.

  Further, even in the method disclosed in Patent Document 3, since the horizontal direction is drawn by the same nozzle group, the film thickness varies for each line and is recognized as unevenness. In the method disclosed in Patent Document 3, in order to completely cancel the variation between the nozzles, as shown in FIG. 8, a black matrix for separating each pixel region is formed in a stripe shape, and the color filter A method of making all nozzle groups for drawing each picture element the same is also conceivable.

  In such a method, there is no theoretical variation in film thickness. However, when ink mixing between specific adjacent picture elements occurs in the inkjet method, it is very difficult to correct the picture elements mixed on the stripe. That is, as shown in FIG. 9, when ink mixing occurs between adjacent picture element lines, the color mixture due to ink mixing spreads over the entire line, and correction is required for the entire line. Therefore, this method is an effective means for preventing unevenness, but is difficult to correct when ink mixing occurs between adjacent picture element lines, and is very disadvantageous in terms of yield.

  The present invention has been made in view of the above-described problems, and its object is to perform drawing that can suppress periodic variations in film thickness when drawing a matrix-like minute region using an inkjet method. To realize the method.

  In order to solve the above problems, the method for drawing a matrix-like microregion using the inkjet method according to the present invention forms a surface water-repellent bank portion on a substrate so that the periphery is surrounded by the bank portion. A first step of forming the microregions in a matrix, a second step of discharging a fluid material into the microregions, and a third step of drying the fluid material into a film, In the second step, the fluid material is also ejected onto the bank part, the minute regions adjacent in the sub-scanning direction are randomly connected, and the film thicknesses in the connected minute regions are averaged. It is said.

  When drawing a matrix-like minute region using the inkjet method, the minute region arranged in the main scanning direction of the nozzle head is drawn by the same nozzle (or nozzle group), and therefore, the film thickness varies from line to line. (Periodic film thickness variation occurs). When the ink jet method is used, the film thickness variation is very small, but there is a problem that the variation has periodicity. For example, when a color filter is created using an ink jet method, periodic film thickness variations of picture elements are easily recognized as color unevenness.

  On the other hand, according to the above configuration, the fluid material is also discharged onto the bank portion, and the minute regions adjacent in the sub-scanning direction are randomly connected. Is averaged, the periodicity of film thickness variation is disturbed, and unevenness cannot be recognized. The fluid material discharged onto the bank part is repelled from the surface of the bank part during drying because the bank part has surface water repellency.

  In the drawing method, the minute area has a substantially rectangular shape. In the second step, the main scanning direction of the nozzle head that discharges the fluid material is set in a direction orthogonal to the longitudinal direction of the minute area. It is characterized by matching.

  According to the above configuration, since each micro area is drawn by a nozzle group including a plurality of nozzles, the original film thickness variation (in the case where the micro areas are not connected by discharging the fluid material onto the bank portion). (Film thickness variation) can be reduced, and the occurrence of unevenness due to film thickness variation can be further reduced by using the above-described method (method of connecting minute regions by discharging a fluid material onto the bank portion). can do.

  Further, in order to solve the above-described problem, the color filter manufacturing method according to the present invention forms a black matrix that forms a surface water-repellent bank on a substrate, so that the periphery is surrounded by the black matrix. Including a first step of forming regions in a matrix, a second step of ejecting ink into the minute region, and a third step of drying the ink to form a film. In the second step, the main scanning direction of the nozzle head that discharges the ink is made to coincide with the direction orthogonal to the longitudinal direction of the minute area, and ink is also discharged onto the black matrix. Is performed to randomly connect the minute regions adjacent to each other in the sub-scanning direction, and the film thickness in the connected minute regions is averaged.

  According to said structure, the color nonuniformity by the periodic film thickness variation of a pixel can be prevented. In the color filter manufacturing method, the first to third steps are executed for each color of the picture elements formed on the color filter.

  In the production of a color filter, the main color scanning direction of the nozzle head is made to coincide with the direction orthogonal to the longitudinal direction of the micro area, so that the same color picture elements are connected when connecting the micro areas. Can do. Further, the random connection of the minute areas can minimize the color mixture area when ink color mixture occurs, and can easily correct the color mixture picture element.

  As described above, the method of drawing a matrix-like microregion using the ink jet method according to the present invention forms a surface water-repellent bank portion on a substrate, so that the microregion is surrounded by the bank portion. A second step of discharging a fluid material into the microregion, and a third step of drying the fluid material to form a film, In the process, the fluid material is also ejected onto the bank portion, the minute regions adjacent in the sub-scanning direction are randomly connected, and the film thicknesses in the connected minute regions are averaged.

  Therefore, by randomly connecting the minute regions adjacent in the sub-scanning direction and averaging the film thickness between the connected minute regions, the periodicity of the film thickness variation can be disturbed, and unevenness cannot be recognized. The effect that it can be made is produced.

  An embodiment of the present invention will be described below with reference to FIGS.

  When a color filter is manufactured using the ink jet method, the general manufacturing procedure will be described as follows. First, a black matrix having a predetermined pattern is formed on a glass substrate serving as a filter substrate. Next, color ink (fluid material) is ejected onto the picture element area (micro area) partitioned by the black matrix pattern, and picture elements are drawn. And the color filter is completed by drying the color ink discharged on the glass substrate.

  The procedure for forming the black matrix will be described more specifically as follows. First, a black matrix material, which is a photosensitive resin material containing a black pigment, is applied onto a glass substrate, and a predetermined dot matrix pattern is formed by performing exposure and development on the black matrix material.

  Next, an ink repellent process is performed on the black matrix. For this purpose, the black matrix pattern is subjected to a surface treatment using a plasma of a gas containing F atoms, and the surface is subjected to an ink repellent treatment. Since F atoms are not substituted on the glass substrate, the glass substrate is made ink-philic and the black matrix is made ink repellent.

  When the black matrix is formed on the glass substrate, color ink is then ejected to the picture element area defined by the black matrix pattern by using an ink jet apparatus to draw the picture element. The color ink used here is a color dispersion in which color pigments are dispersed. The present invention is characterized by a picture element drawing process using an inkjet method, and this picture element drawing process will be described in detail below.

  In the method for manufacturing a color filter according to the present embodiment, the inkjet device is in the horizontal direction with respect to the dot matrix (meaning the horizontal direction assumed in the display screen in the display element in which the color filter is used: horizontal direction) Draw a picture element. Here, drawing a picture element from the horizontal direction will be described with reference to FIG.

  A pattern by the black matrix 11 is formed on the glass substrate 10 before the picture element is drawn. In the color filter manufactured by this method, picture elements of the same color are arranged in the vertical direction (in the display element in which the color filter is used, the vertical direction assumed in the display screen: also referred to as the vertical direction). Ink is discharged as described above. The nozzle head 20 in the inkjet apparatus includes a plurality of nozzles 21, and the longitudinal direction of the nozzle head 20, that is, the arrangement direction of the nozzles 21 is aligned with the vertical direction, and the drawing direction by the nozzle head 20, that is, the main scanning direction is horizontal. Adapted to the direction.

  In the color filter, the picture element region has a substantially rectangular shape with the longitudinal direction as the longitudinal direction, and the main scanning direction of the nozzle head 20 is aligned with the horizontal direction. It means matching with the direction orthogonal to the longitudinal direction of the picture element region. This is intended to reduce the original film thickness variation by drawing the pixel area with a nozzle group composed of a plurality of nozzles 21. However, in the case of manufacturing a color filter, adjacent pixel element areas are used. This is also a configuration for enabling connection between the same-color picture elements when performing connection (details will be described later).

  In this method, since one nozzle head 20 is used for drawing a picture element for one color, in order to draw picture elements of three colors of R (red), G (green), and B (blue). Are provided with three nozzle heads 20A to 20C in the ink jet apparatus. When the length of the glass substrate 10 in the vertical direction is larger than the width of the nozzle head in the longitudinal direction, the nozzle head 20 is moved relative to the glass substrate 10 by the width of the nozzle head 20. The color filter picture elements may be drawn by performing drawing in the main scanning direction a plurality of times.

  As described above, the nozzle group used for each picture element is determined simply by drawing the picture element from the horizontal direction on the dot matrix, so that unevenness due to periodic film thickness variations is caused. Will occur. This is a problem that exists in the above-described conventional method (Patent Document 3). First, the reason for the occurrence of this problem will be described with reference to FIG.

  In the nozzle head 20 shown in FIG. 3, ink is ejected to one picture element by each of the nozzle groups 211, 212, 213, and 214 in a certain picture element line extending in the vertical direction. In the conventional method, the nozzles on the black matrix 11 do not discharge ink (that is, are not used for drawing).

  Here, it is assumed that the nozzle group 212 has a larger ink discharge amount than the other nozzle groups, and the nozzle group 214 has a smaller ink discharge amount than the other nozzle groups. In such a case, the picture element drawn by the nozzle group 212 has a large film thickness, and the picture element drawn by the nozzle group 214 has a small film thickness. Such variation in film thickness is maintained even after the ink is dried. Since the nozzle head 20 draws picture elements while being scanned in the horizontal direction, a light and dark line extending in the horizontal direction is formed. When the drawing operation is performed a plurality of times while moving the nozzle head 20 in the sub-scanning direction with a constant width, the light and dark lines are generated with a period in the sub-scanning direction.

  Next, a drawing method according to the present embodiment will be described with reference to FIG.

  In the nozzle head 20 shown in FIG. 1 as well, ink is discharged to one picture element by each of the nozzle groups 211, 212, 213, and 214 for a certain picture element line extending in the vertical direction. However, in the method according to the present embodiment, the nozzles on the black matrix 11 may also eject ink to connect adjacent picture elements. In this respect, the method according to the present embodiment is a conventional method. Is different.

  When ink is ejected by the nozzles 21a applied on the black matrix 11 and adjacent picture elements are connected, ejection ink is mixed in the two connected picture elements, and the film thickness is averaged. In addition, since the inks mixed at this time are the same color inks, no ink color mixing occurs.

  Since the black matrix 11 has strong ink repellency, the ink is repelled from the black matrix 11 as the ink dries, and finally the ink ejected on the black matrix 11 also fits in the picture element. And dry.

  In the present embodiment, connection between adjacent picture elements is performed at random. That is, in FIG. 1, the nozzles 21a applied on the black matrix 11 do not eject ink to all the pixel lines extending in the vertical direction. If the lines change, adjacent nozzles are connected. The nozzle used to do this is also changed.

  As described above, in the method according to the present embodiment, the ink amount of the mixed picture elements, that is, the film thickness of the picture elements is averaged by randomly mixing adjacent picture elements, and the film thickness variation is periodically performed. It is changing from regular variation to random variation.

  In the example of FIG. 1, since the connection between adjacent picture elements is performed by ink ejection onto the black matrix 11, the two picture elements connected thereby have an average film thickness between the two picture elements. However, the film thickness is larger for other picture elements. However, since the connection between adjacent picture elements is made at random, the increase in the film thickness of the connected picture element due to the ink ejection onto the black matrix 11 also occurs randomly and does not have periodicity. It is hard to be recognized as.

  That is, the problem of color unevenness in the conventional color filter is not caused by the variation in the film thickness of the picture element itself, but is caused by the variation in the film thickness having periodicity. The variation of the color filter film thickness due to the variation between the nozzles of the inkjet is very small, and the uniformity of the variation is equal to or higher than that of a normal photolithography method. However, in the photolithography method, the variation in film thickness is close to gradation, so that it is difficult to recognize as unevenness. On the other hand, in the ink-jet method, even if the amount of film thickness variation is minute, since it periodically exists, it is easily recognized as unevenness. That is, if the period of the film thickness variation can be disturbed, it is not recognized as unevenness.

  In the present invention, adjacent picture elements are mixed randomly, and the droplets between the mixed picture elements are averaged, thereby making the film thickness variation random. The film thickness variation is not completely corrected, but the film thickness variation is changed from a periodic layout to a random layout, so even if there is a film thickness variation, it will not be recognized as unevenness. It is characterized by.

  In the adjacent picture element, if the amount of ink ejected into the picture element is reduced by the amount of ink ejected onto the black matrix 11, the amount of ink ejected changes even when compared with the surrounding picture elements. Without increasing the thickness of the connected picture element due to the ejection of ink onto the black matrix 11, it can be easily eliminated.

  Further, in the method according to the present embodiment, not all adjacent same-color picture elements (vertically adjacent picture elements) are connected, but only a part of adjacent picture elements are connected randomly. . Of course, if all the same color picture elements are connected and the total film thickness in the same color line is averaged, it is more ideal from the viewpoint of eliminating unevenness. However, in such a case, as in the example described in FIG. 9, there is a problem that when ink mixing occurs between adjacent lines (between different color lines), it becomes difficult to correct the ink.

  On the other hand, in the method of connecting some of the adjacent picture elements at random, even if ink mixing occurs between the picture elements adjacent in the horizontal direction, the color mixture of the picture elements due to this ink mixing spreads over the entire line. The correction is also easy. That is, as shown in FIG. 4, even if ink is mixed between horizontally adjacent picture elements, the mixed color area is generated in units of picture elements, so that it can be minimized.

  In general, correction of a picture element in which ink color mixture has occurred is performed by removing the ink of the color mixture picture element by laser irradiation and ejecting the ink to the removed area again. For this reason, the smaller the color mixture region, the easier the correction.

  In addition, in the method according to the present embodiment, it is preferable that the connection of the same color picture element is a maximum of two if the correction when the mixed color picture element of ink is generated is taken into consideration. Further, it is preferable that picture elements adjacent in the vertical direction are not adjacent to each other between the lines arranged in the horizontal direction. That is, in FIG. 5A to FIG. 5C, the picture elements connected in the vertical direction in order to average the film thickness are indicated by hatching, but in the form shown in FIG. When ink mixing occurs at the middle x mark, ink mixing occurs in three picture element regions. On the other hand, FIG. 5B is an example in which the same color picture elements are connected by three picture elements. In this case, when ink mixing occurs at the location indicated by X in the figure, it is equivalent to four picture elements. Ink color mixing occurs in the pixel area. FIG. 5C shows an example in which picture elements adjacent in the vertical direction are adjacent in the horizontal direction. In this case as well, ink mixing occurs at the location indicated by a cross in the figure. Ink color mixing occurs in four picture element regions.

  In general, the nozzles of the ink jet apparatus are formed at a specific pitch, and the nozzle pitch and the pitch of the display elements hardly coincide with each other. Therefore, as shown in FIG. 6, a method has been devised in which the nozzle pitch is matched with the pitch of the display elements by rotating the nozzle head 20. In addition, with this method, nozzles that can eject ink onto the black matrix 11 can be present at all connection locations of picture elements arranged in the vertical direction.

  In the present invention, it is possible to easily mix adjacent picture elements by using the nozzles on the black matrix. In addition, since the mixing position can be controlled depending on whether or not the nozzles are discharged, it is possible to arbitrarily set a discharge pattern that makes the film thickness random.

  When such a discharge pattern was used to form a color filter and a liquid crystal display element, a good display element with no noticeable unevenness was formed.

  In addition, the method of drawing a micro area | region using the inkjet in this invention is not limited to manufacture of the above color filters. Other application examples of the present invention include a method for producing an organic EL element, a method for producing a transparent electrode in a liquid crystal display element, and the like.

  Also in the organic EL element which is a self-luminous display element, formation of the hole transport layer, the light emitting layer, etc. by the inkjet method is examined. Although the hole transport layer and the light emitting layer in the organic EL element are also formed as a matrix-like minute region, variations in the film thickness of these formed layers appear as variations in luminance. Therefore, if there are periodic variations in film thickness, there will be periodic variations in luminance, which will be recognized as unevenness.

  For this reason, even in the formation of organic EL elements, if the hole transport layer and the light emitting layer are formed by using the present invention, the variation in luminance is within the display surface by randomizing the film thickness variation of these layers. It became random and it was confirmed that unevenness became inconspicuous as a whole.

  In liquid crystal display elements and the like, ITO (Indium Tin Oxide) is widely used as a transparent electrode. For the transparent electrode, ITO is generally formed by a sputtering method, and patterning of the transparent electrode is performed using photolithography and etching.

  In recent years, a method for efficiently forming a transparent electrode pattern by applying fine particle dispersed ITO with an inkjet apparatus has been studied. Even in this case, the periodic film thickness variation formed by the ink jet apparatus is recognized as unevenness. For this reason, when a transparent electrode is formed using the present invention, when a fine particle dispersion type ITO is ejected by an ink jet method, a display element in which the occurrence of film thickness variation is randomly dispersed is formed, and a good display element is obtained. It was.

  When drawing a microscopic area in a matrix using the inkjet method, it is possible to suppress variations in periodic film thickness, so that unevenness that is easily recognized by having periodicity can be reduced, and pixel formation of a color filter, It can be applied to uses such as formation of organic EL elements and formation of transparent electrodes.

1 is a diagram illustrating an embodiment of the present invention and a drawing method of a picture element at the time of manufacturing a color filter. It is a figure explaining drawing of the picture element from a horizontal direction in color filter manufacture. It is a figure which shows the comparative example of this invention and shows the drawing method of the pixel at the time of color filter manufacture. It is a figure which shows the state when the color mixture of an ink arises in the color filter by which a picture element is drawn by the method of this invention. FIGS. 5A to 5C are plan views showing picture elements that need to be corrected when ink color mixture occurs. It is a figure which shows the state which draws a picture element by rotating a nozzle head. It is a figure which shows a prior art and is a figure explaining drawing of the picture element from a vertical direction in color filter manufacture. It is a figure which shows a prior art and is a figure explaining drawing of the striped picture element from a horizontal direction in color filter manufacture. FIG. 9 is a diagram illustrating a state where color mixing of ink occurs in a color filter in which picture elements are drawn by the method illustrated in FIG. 8.

Explanation of symbols

10 Glass substrate (substrate)
11 Black matrix (bank part)
20 Nozzle head 21 Nozzle

Claims (3)

Forming a surface water-repellent bank on the substrate, thereby forming a minute region surrounded by the bank in a matrix;
A second step of discharging a fluid material into the minute region;
A third step of drying the fluid material into a film,
In the second step, the fluid material is also discharged onto the bank portion, the minute regions adjacent in the sub-scanning direction are randomly connected, and the film thickness in the connected minute regions is averaged. A method for drawing a matrix-like micro-region using an ink jet method. The minute area has a substantially rectangular shape,
2. The matrix using the ink jet method according to claim 1, wherein in the second step, a main scanning direction of a nozzle head that discharges the fluid material is made to coincide with a direction orthogonal to a longitudinal direction of the minute region. To draw a microscopic area. Forming a black matrix that forms a surface water-repellent bank on a substrate, thereby forming a micro region surrounded by the black matrix in a matrix;
A second step of discharging ink into the minute region;
A third step of drying the ink to form a film,
The minute area has a substantially rectangular shape,
In the second step, the main scanning direction of the nozzle head that discharges the ink is made to coincide with the direction orthogonal to the longitudinal direction of the minute region, and ink is also discharged onto the black matrix, so that the sub-scanning direction A method for producing a color filter, comprising: randomly connecting the minute regions adjacent to each other and averaging the film thickness in the connected minute regions.

Images