JP2006308974A - Color filter, manufacturing method thereof, and color filter manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color filter having no film thickness unevenness even when ink having high viscosity is used.
In a manufacturing method of a color filter that ejects ink to an object to be colored 4b on a substrate 3 by an ink jet method, three selected from a plurality of nozzles 1b are applied to one object to be colored 4b. One set of nozzles 1b is used, and ink is simultaneously ejected from the set of nozzles 1b.
[Selection] Figure 2

Description

  The present invention relates to a color filter having a uniform film thickness formed by ejecting ink from an inkjet head, a method for manufacturing the same, and an apparatus for manufacturing the color filter. For example, each pixel of a substrate is colored. The present invention relates to a color filter for a liquid crystal display formed by the above, a manufacturing method thereof, and a manufacturing apparatus of the color filter.

  Today, for example, with the development of thin liquid crystal televisions, personal computers, mobile phones, and the like, the demand for liquid crystal displays, particularly color liquid crystal displays, is increasing. However, the price of the liquid crystal panel is still high, and further cost reduction is required. In particular, there is an increasing demand for cost reduction of a color filter having a large specific gravity.

  As a method for producing a color filter, a dyeing method, a pigment dispersion method, an electrodeposition method, a printing method, an ink jet method, and the like have been proposed.

  For example, in Patent Document 1, as an ink jet method, an ink (colored liquid) containing each of three colors of red, green, and blue is ejected onto a substrate using an ink jet dihead, and then each ink is discharged. A method for forming a colored portion of a color filter by drying is disclosed.

  Patent Document 2 discloses a method for forming a colored portion of a color filter by simultaneously discharging ink (colored liquid) to a plurality of colored portions using an inkjet head having a plurality of nozzles as an inkjet method. Is disclosed.

  FIG. 6 is a cross-sectional view illustrating an example of an arrangement relationship between an inkjet head having a plurality of nozzles and a substrate on which a portion to be colored (pixels) is formed. In this configuration, the inkjet heads 102a to 102c that discharge inks of R (red), G (green), and B (blue) colors are scanned in the scanning direction A while the substrate 103 on which the color filter is formed is covered. Ink is ejected from the nozzles 101a to 101c to the coloring portions 104a to 104c. The colored portions 104a to 104c correspond to the colors (R, G, and B) of the inkjet heads 102a to 102c, respectively.

  Further, in the configuration of FIG. 6, the nozzle pitch 105 of the inkjet head 102a and the pitch of the colored portion to be colored in the same color (the pitch 106 of the colored portions 104a to 104a to be colored R in FIG. 6) match. (Nozzle pitch 105 <pitch 105). In such a case, the inkjet heads 102a to 102c are arranged to be inclined with respect to the arrangement direction of the portions to be colored 104a, 104b, 104c. For example, ink is ejected from nozzles 101a-101a (filled nozzles 101a in FIG. 6) corresponding to the colored portions 104a-104a of the same color with the inkjet head 102a tilted. Thereby, the to-be-colored part 104a-104a of the same color can be colored simultaneously.

As described above, in the configuration of FIG. 6, a color filter coloring portion having a pixel pitch 106 different from the nozzle pitch 105 is formed by using one inkjet head 102 a to 102 c having a plurality of nozzle holes for each color. Can do.
JP 59-75205 A (published April 27, 1984) Japanese Patent Laid-Open No. 9-101212 (released on April 15, 1997)

  However, in the conventional configuration, when high-viscosity ink is used, there is a problem that the ink does not spread over the entire portion to be colored and the film thickness cannot be made uniform.

  Specifically, in the production of a color filter, an ink having a higher viscosity than that used in an ink jet printer is used. This high-viscosity ink contains a high-concentration pigment component (for example, about 30%), and the viscosity is, for example, 15 cP. The reason for using high-viscosity ink is to prevent color mixing between adjacent colored portions (pixels) on the substrate on which the color filter is formed.

  However, in the configuration of Patent Document 2, when the nozzle pitch is small with respect to the size of the pixel, it is possible to draw using a plurality of nozzles, whereas the size of the pixel When the nozzle pitch is the same or larger, drawing can be performed using only one nozzle. When only one nozzle is used, in consideration of ink spreading, it is necessarily landed near the center of the pixel. For this reason, with the configuration of Patent Document 2, the landing position can be obtained only near the center of the pixel. However, as in the configuration of Patent Document 2, when high-viscosity ink is landed near the center of the colored portion, the spread of the ink after landing is reduced. As a result, even after the ink is dried, the ink does not spread over the entire colored portion, and the thickness (film thickness) of the ink in the colored portion is not uniform. In particular, the spread of ink to the end of the part to be colored has deteriorated. For this reason, film thickness unevenness (also referred to as coating unevenness and pigment unevenness) occurs, resulting in poor color filter performance.

  It is also conceivable to eliminate the uneven film thickness by repeatedly scanning the colored portion where the uneven film thickness has occurred and discharging ink. However, since the ink used for manufacturing the color filter has high volatility, if the discharge timing is slightly different, drying unevenness occurs due to the difference in drying time, and thus the film thickness unevenness cannot be solved.

  In addition, for example, in liquid crystal television displays currently on the market, there are many sizes of liquid crystal panels, from about 20 inches to nearly 50 inches. For example, in a 22-inch WXGA (Wide extended Graphics Array) type liquid crystal panel, the pixel pitch is 356.5 μm, and the pixel width per color is 118.8 μm. On the other hand, in a 45-inch WXGA type liquid crystal panel, the pixel pitch is 729.3 μm, and the pixel width per color is 243.1 μm.

  As described above, since the size and pixel pitch of the liquid crystal display are various, when a single inkjet head is used to support various pixel pitches, the landing position for landing the ink on the pixel of the substrate is appropriately set. Must be set.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a color filter having no film thickness unevenness even when using ink having a particularly high viscosity, a method for manufacturing the color filter, and a device for manufacturing the color filter. It is to provide.

  In order to solve the above-described problems, a color filter manufacturing method of the present invention is a method for manufacturing a color filter that ejects ink by an inkjet method to a colored portion on a substrate. And a discharge step of simultaneously discharging ink from a nozzle set including two or more nozzles selected from a plurality of nozzles.

  The color filter manufacturing method is a method of forming a color filter by ejecting ink by an ink jet method. The formation of the color filter by the ink jet method is performed by discharging ink from the nozzles to the colored portion of the substrate. The ink ejected to the colored part spreads after landing on the colored part. And the colored part (colored area | region) corresponding to each color of a color filter is formed when the ink which spread to the to-be-colored part dries.

  According to the above invention, in the ejection step, ink is ejected from a nozzle set composed of two or more nozzles to one colored portion. Thereby, ink is landed from a plurality of nozzles to one colored portion by one ink discharge. For this reason, ink can be ejected to a plurality of different points of the colored portion by one ink ejection. As a result, for example, even when ink is ejected near the center of the colored portion, the ink spreads not only in the vicinity of the central portion but also in the end direction of the colored portion. Therefore, even when a highly viscous ink is used, it is possible to produce a color filter with extremely small film thickness unevenness by spreading the ink over the entire portion to be colored.

  In the color filter manufacturing method of the present invention, it is preferable that adjacent nozzles are used as the nozzle set in the ejection step.

  According to the above invention, adjacent nozzles are used as a nozzle set selected from a plurality of nozzles in the ejection step. For this reason, it is possible to reduce the number of nozzles from which ink is not discharged and to efficiently use a plurality of nozzles. If the nozzle sets are also adjacent to each other, a plurality of nozzles can be used more efficiently.

  In the method for producing a color filter of the present invention, in the ejection step, it is preferable to use, as the nozzle set, a nozzle whose ink ejection direction is inclined toward the center of the colored portion.

  According to said invention, the ink discharge direction of a nozzle set inclines in the center part of a to-be-colored part. For this reason, even when the width of the nozzles at both ends constituting the nozzle set is larger than the width of the colored portion, the colored portion is colored by inclining the ink ejection direction according to the width of the colored portion. be able to. As a result, the number of nozzles constituting the nozzle set can be increased as compared with the case where a nozzle set that does not tilt the ink ejection direction is used. As a result, ink can be ejected using a nozzle set composed of a larger number of nozzles for one color. Accordingly, it is possible to further spread the ink over the entire portion to be colored and manufacture a color filter with extremely small film thickness unevenness. Such a configuration is particularly useful for manufacturing a color filter for a large liquid crystal panel, for example.

  In the color filter manufacturing method of the present invention, it is preferable that the distance between the substrate and the nozzle is changed according to the size of the portion to be colored in the ejection step.

  According to the above invention, in the ejection step, ink is ejected from the nozzle by changing the distance between the substrate and the nozzle in accordance with the size of the portion to be colored that varies depending on the size of the substrate. Accordingly, the size of the colored portion (the size of the substrate) is maintained by maintaining the distance between the substrate and the nozzle so that the landing position of the ink on the colored portion is almost unchanged (allowable range). Accordingly, the color filter can be manufactured by changing the distance between the substrate and the nozzle to an optimum position.

  In the method for producing a color filter of the present invention, in the ejection step, the angle between the substrate and the nozzle is changed so that the pitch between the colored portions of the same color and the pitch between the nozzle sets of the same color are substantially the same. It is preferable to make it.

  According to the above invention, the angle between the substrate and the nozzle is changed so that the pitch between the parts to be colored of the same color and the pitch between the nozzle sets of the same color substantially coincide. Here, if the nozzle sets (nozzle arrangement direction) are inclined with respect to the substrate, the pitch between the nozzle sets (between nozzles) during ink ejection becomes smaller than when the nozzle sets are not inclined. The “pitch between nozzle sets of the same color” indicates a substantial pitch between nozzle sets when ink is ejected to the colored portion.

  According to the above invention, the ink is ejected in a state where the pitch between the colored portions of the same color and the pitch between the nozzle sets of the same color at the time of ink ejection are substantially matched. That is, when the pitch between the colored parts and the pitch between the nozzle sets do not match, the angle between the substrate and the nozzle is adjusted so that the pitches substantially match. Thereby, a color filter can be manufactured according to board | substrate size (size of a to-be-colored part).

  In the color filter manufacturing method of the present invention, it is preferable that the substrate or the nozzle is rotated in the ejection step.

  According to said invention, the angle of a board | substrate and a nozzle can be changed by rotating a board | substrate or a nozzle. Thereby, a color filter can be manufactured according to board | substrate size (size of a to-be-colored part).

  In order to solve the above problems, a color filter manufacturing apparatus of the present invention has a plurality of nozzles in a color filter manufacturing apparatus that ejects ink to a plurality of colored portions on a substrate by an inkjet method. In addition, an ink jet head that discharges ink simultaneously from two or more nozzles selected from a plurality of nozzles is provided for one colored portion.

  According to the above-described invention, similar to the method for producing a color filter of the present invention, it is possible to produce a color filter with extremely small film thickness unevenness by spreading ink over the entire portion to be colored.

  In order to solve the above problems, the color filter according to the present invention is characterized in that the uneven thickness of the colored portion is 1% or less. According to the above invention, a color filter with extremely small film thickness unevenness can be provided.

  A display panel according to the present invention includes the color filter according to the present invention. According to said invention, the said display panel can provide the display panel provided with the color filter of this invention with a very small film thickness nonuniformity. Here, the display panel only needs to include a color filter, and examples thereof include a liquid crystal display panel.

  As described above, the color filter manufacturing method and manufacturing apparatus according to the present invention are configured to simultaneously eject ink from a nozzle set including two or more nozzles selected from a plurality of nozzles to one colored portion. It is.

  According to the present invention, it is possible to spread the ink not only at the central portion of the colored portion of the substrate but also at the end portion. Therefore, it is possible to reduce the film thickness unevenness after the ink is dried and to produce a color filter having a uniform film thickness.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. The present invention is not limited to the following embodiments.

  The color filter manufacturing apparatus of the present invention manufactures a color filter having no film thickness unevenness using a high-viscosity ink in the manufacture of a color filter by an inkjet method.

  FIG. 1 is a perspective view of an ink jet head (coating mechanism) used in the color filter manufacturing apparatus of the present embodiment.

  The color filter manufacturing apparatus of this embodiment forms a colored portion of a color filter by discharging ink from an inkjet head 2 as shown in FIG.

  As shown in FIG. 1, the inkjet head 2 has a configuration in which a nozzle plate 10 is formed at the center of a head chip 11.

  The nozzle plate 10 is a portion that ejects ink for forming a color filter in the inkjet head 2. In the nozzle plate 2, three rows of nozzles 1a to 1c corresponding to red (R), green (G), and blue (B) are formed. For each color, a plurality of nozzles 1a to 1c are linearly arranged. Each of the nozzles 1a to 1c is designed to have a predetermined nozzle pitch 5 (interval between adjacent nozzles).

  In the present embodiment, the nozzle plate 10 is provided with 30 nozzles 1a to 1c (total 90) for each color. The nozzle pitch 5 is designed to be 243.1 μm. This nozzle pitch 5 is the same as the pixel pitch per color in a 45-inch WXGA type liquid crystal panel.

  Here, FIG. 2 is a cross-sectional view of the nozzle plate 10 in which the inkjet head 2 of FIG. 1 is cut by a broken line. That is, FIG. 2 shows a cross section of a portion of the nozzle plate 2 that ejects green ink.

  As shown in FIG. 2, the nozzle plate 10 includes a piezoelectric element 12. The nozzles 1b are adjacent to each other through the piezoelectric element 12. The piezoelectric element 12 is a wall portion that partitions the nozzle 1b.

  For example, lead zirconate titanate (PZT) can be used as the piezoelectric element 12.

  A nozzle hole (ejection port) 8 for ejecting ink is formed in the tip part (tip part of the nozzle 1 b) 14 of the nozzle plate 10. The nozzle hole 8 is formed by a processing apparatus such as an excimer laser, for example. The nozzle hole 8 is narrower than the nozzle channel 13. That is, the diameter of the nozzle hole 8 is smaller than the diameter of the nozzle channel 13.

  A surface treatment layer (not shown) having ink repellency (not shown) is formed on the surface (tip portion 14) of the nozzle plate 10 to prevent ink from adhering to the vicinity of the nozzle holes 8.

  The nozzle 1b ejects ink from the nozzle hole 8 via the ink flow path 13 from above in FIG. The ink is ejected in the ejection direction (flying direction) indicated by the arrow shown in FIG. 2 with respect to the substrate 3 forming the color filter.

  That is, when a voltage is applied to the piezoelectric element 12, the piezoelectric element 12 expands and contracts and vibrates, and a pressure chamber (not shown) is driven by the pressure fluctuation. As a result, ink is ejected from the nozzle hole 8 via the ink flow path 13. At this time, if the voltage applied to the piezoelectric element 12 is controlled, the ink discharge amount can be adjusted. The ink ejection amount may be set according to the size of the colored portions 4a to 4c, the ink viscosity, the ink landing position, and the like, and is not particularly limited.

  In the above description, ink is ejected by the piezoelectric element 12. However, for example, the ink can be heated to generate bubbles in the ink, and the ink can be ejected by volume expansion of the bubbles. Also in this case, the amount of ink ejected from the nozzle hole 8 can be adjusted by controlling the voltage.

  Here, ink discharge from the nozzles 1a to 1c, which is a characteristic part of the present invention, will be described with reference to FIGS. FIG. 3 is a diagram illustrating the landing positions of the ink ejected from the nozzles 1 b, and FIG. 4 is a diagram illustrating the positional relationship between the nozzle plate 10 and the substrate 3.

  As shown in FIG. 4, the colored portions 4 a to 4 c arranged in the order of R, G, and B are formed in stripes on a substrate 3 on which ink is ejected (substrate on which a color filter is formed) 3. . The colored portions 4a to 4c are regions that become colored portions of the color filter after the ink is dried by discharging the ink from the inkjet heads 2a to 2c.

  The inkjet head 2 according to the present embodiment is characterized in that ink is simultaneously ejected from a plurality of nozzles 1 a to 1 c of the same color onto one colored portion 4 a to 4 c of the substrate 3.

  More specifically, in the present embodiment, as shown in FIG. 2, the inkjet head 2 includes three nozzles 1 b each composed of a central nozzle 1 b and two nozzles 1 b adjacent to the central nozzle 1 b. Ink is ejected as a set (nozzle set). Furthermore, the ink ejection directions of the central nozzle 1b and the two nozzles 1b adjacent to the central nozzle 1b are different.

  Specifically, the central nozzle 1 b ejects ink vertically downward with respect to the formation surface of the portions to be colored 4 a to 4 c on the substrate 3. That is, the angle between the central part of the three nozzles 1b and the vertical direction of the substrate 3 is 0 degree.

  On the other hand, the adjacent nozzle 1b ejects ink at an angle inclined with respect to the formation surface of the colored portions 4a to 4c on the substrate 3 toward the center nozzle 1b side (inner side) rather than vertically downward. Here, the angle of the ink discharge direction of the adjacent nozzle 1b is set to 8.64 ° with respect to the ink discharge direction of the central nozzle 1b. That is, the angle between the two end portions of the three nozzles 1b and the vertical direction of the substrate 3 is an angle of 8.64 degrees. Thus, the ink discharge direction of the adjacent nozzle 1b is inclined toward the center of the colored portion 4b.

  This angle is set according to, for example, the distance between the substrate 3 and the inkjet heads 2a to 2c (nozzles 1a to 1c) and the ink landing positions 17 and 18 (see FIG. 4 described later) to be realized. The That is, the landing position of the ejected ink is determined by this angle. Even when the same landing position is obtained, the set angle differs depending on the viscosity of the ink. That is, this angle is set according to the spread of ink after landing.

  FIG. 3 shows a result of ejecting ink from the three nozzles 1b to the colored portion 4b. As shown in FIG. 3, ink is landed at three places on the colored portion 4b by one discharge from the three nozzles 1b. That is, ink is ejected to the ink landing position 17 from the central nozzle 1b and the ink landing position 18 from two adjacent nozzles 1b by one ejection. By performing such ink discharge while scanning the substrate 3 and the inkjet head 2, the entire portion to be colored 4b can be colored.

  In FIG. 3, for convenience, when the width 7 of one colored portion is “pixel width”, the pixel width 7 of the colored portion 4b is 242 μm in FIG. In FIG. 3, the distance (center distance) between the ink landing position 17 discharged from the central nozzle 1b and the ink landing position 18 discharged from the adjacent nozzle 1b is 91 μm. Further, the distance between the end of the colored portion 4b and the center of the ink landing position 18 is 30 μm. The pixel width 7 is a width in a direction orthogonal to the scanning direction A of the inkjet head 2.

  In the inkjet head 2 according to the present embodiment, the ink is ejected from the three nozzles to each of the colored portions 4a to 4c. As shown in FIG. 4, the inkjet head 2 of FIG. 1 includes inkjet heads 2 a to 2 c for each color ink. In FIG. 4, in each of the inkjet heads 2 a to 2 c, the filled nozzles 1 a to 1 c become the central nozzles 1 a to 1 c, and ink is simultaneously supplied from the three nozzles 1 a to 1 c including the adjacent nozzles 1 a to 1 c. Discharged. Thereby, the to-be-colored parts 4a-4c can be colored uniformly.

  Here, as described above, in the present embodiment, each of the nozzles 1a to 1c ejects ink with one set of three nozzles for one portion to be colored. In each of the inkjet heads 2a to 2c, the nozzles 1a to 1c are arranged at a predetermined nozzle pitch 5. For this reason, the pitch between the center nozzle of a nozzle set and the center nozzle of the adjacent nozzle set (pitch between center nozzles) is also a predetermined value.

  Further, the portions to be colored 4 a to 4 c on the substrate 3 are formed with a predetermined pixel width 7. Further, the pitch between adjacent colored portions (for example, the pitch between the colored portion 4a and the adjacent colored portion 4b) is also a predetermined pitch. For this reason, the to-be-colored parts of the same color (for example, the pitch between the to-be-colored parts 4a-4a (pixel pitch 6 of the same color) also becomes a predetermined value.

  The pixel width 7 is the width of one of the colored portions 4a to 4c, and the pixel pitch 6 is the width of the colored portions 4a-4a between the same colors.

  Since the nozzle pitch 5, the pitch 16 between the central nozzles, the pixel width 7, and the pixel pitch 6 of the same color are arbitrarily set values, they change according to the inkjet heads 2a to 2c and the substrate 3. It is.

  Therefore, when the inkjet heads 2a to 2c having the nozzles 1a to 1c arranged at the predetermined nozzle pitch 5 are used, the pitch 16 between the central nozzles and the pixel pitch 6 of the same color may or may not match. is there.

  In any case, the color filter manufacturing apparatus of the present embodiment can uniformly color the portions to be colored 4a to 4c. FIG. 4 is a diagram showing the positional relationship between the inkjet heads 2a to 2c and the substrate 3 when the pitches match, and FIG. 5 shows the positional relationship between the inkjet head 2a and the substrate 3 when the matches do not match. FIG.

  That is, in FIG. 4, the pitch 6 between the colored portions of the same color (for example, the pitch between the colored portions 4a-4a in FIG. 4) 6 is substantially equal to the pitch 16 between the central nozzles 1a-1a. In this case, ink is ejected with the inkjet heads 2 a to 2 c being parallel to the formation surfaces of the colored portions 4 a to 4 c of the substrate 3. As a result, the ink is landed on the colored portions 4 a to 4 c in parallel with the direction of the pixel width 7. And by keeping the parallel and scanning the inkjet heads 2a to 2c in the scanning direction A, the colored portion 4a is colored. In this way, when the pitch 16 between the central nozzles and the pixel pitch 6 of the same color coincide with each other, the portions to be colored 4a to 4c can be uniformly colored.

  On the other hand, in FIG. 5, the pitch 6 between the colored portions 4a-4a of the same color is different from the pitch 16 between the central nozzles 1a-1a (for example, pitch 6 <pitch 16). In this case, the ink jet heads 2 a to 2 c are inclined with respect to the formation surface of the colored portions 4 a to 4 c of the substrate 3 to discharge ink. Here, the degree of inclination (angle) may be such that the pixel pitch 6 of the same color and the pitch 19 between the substantial center nozzles at the time of inclination substantially coincide. Accordingly, the ink is landed on the portions to be colored 4 a to 4 c in a state inclined with respect to the direction of the pixel width 7. And the to-be-colored part 4a is colored by scanning the inkjet heads 2a-2c in the scanning direction A, maintaining the inclination. In this way, even when the pitch 16 between the center nozzles and the pixel pitch 6 of the same color do not match, the colored portions 4a to 4c can be uniformly colored.

  As described above, the color filter manufacturing apparatus according to the present embodiment scans if the pixel pitch 6 between the colored portions 4a-4a of the same color and the pitch 16 between the central nozzles 1a-1a are the same. The to-be-colored parts 4a to 4c can be colored without inclining the inkjet heads 2a to 2c with respect to the direction. On the other hand, when the pixel pitch 6 and the pitch 16 are different, the colored portions 4a to 4c can be colored by inclining the ink jet heads 2a to 2c.

  Therefore, a color filter can be manufactured using the inkjet heads 2 a to 2 c regardless of the pixel pitch 6 of the substrate 3. Usually, the size of the liquid crystal display and the pixel pitch 6 vary. The color filter manufacturing apparatus of this embodiment can manufacture color filters for substrates 3 having various pixel pitches 6 in correspondence with liquid crystal panels of various sizes.

  As described above, the color filter manufacturing apparatus according to the present embodiment is not limited to the pitch 6 between the colored portions 4a-4a of the same color and the pitch 16 between the central nozzles 1a-1a. -4c can be uniformly colored. And the coloring part of a color filter is formed by drying of the ink after coloring, and manufacture of a color filter is completed.

  In the color filter manufacturing apparatus of the present embodiment, if the distance between the inkjet heads 2a to 2c (nozzles 1a to 1c) and the substrate 3 is too close or too far, the ink landing positions 17 and 18 are surely set. In some cases, it cannot be realized.

  Therefore, in the color filter manufacturing apparatus of the present embodiment, in order to realize the ink landing positions 17 and 18, the distance between the inkjet heads 2a to 2c (nozzles 1a to 1c) and the substrate 3 is set to an optimum position. Yes.

  Here, the “optimum position” is a position where the ink jet heads 2a to 2c and the substrate 3 do not come into contact with each other, and for example, ink droplets ejected from the nozzles 1a to 1c are caused to flow by the surrounding airflow. This indicates a position where the ejected ink can land at the position where it should land. The “optimum position” is, for example, a range in which the ink droplet landing position is measured by changing the distance between the ink jet heads 2a to 2c and the substrate 3, and the ink droplet landing position does not change (that is, a color filter is formed). In this case, the position can be obtained by setting the farthest position within the allowable range of positional deviation.

  For example, the distance between the inkjet heads 2a to 2c (nozzles 1a to 1c) and the substrate 3 is set to 1 mm in order to reliably realize the ink landing positions 17 and 18 as shown in FIG. In the three nozzles 1b described above, the angle of the ink ejection direction of the adjacent nozzle 1b (8.64 ° in FIG. 2) is the distance (1 mm) between the inkjet heads 2a to 2c (nozzles 1a to 1c) and the substrate 3. And the ink landing positions 17 and 18 in FIG.

  As described above, in the color filter manufacturing apparatus of the present embodiment, the distance between the ink jet heads 2a to 2c (nozzles 1a to 1c) and the substrate 3 is set to an optimum position, so that the intended ink landing can be ensured. Positions 17 and 18 can be realized. Thereby, a color filter with a more uniform film thickness can be manufactured.

  Note that the inclination angle of the inkjet heads 2a to 2c and the distance (optimum position) between the substrate 3 and the nozzle 1b can be set based on, for example, the portions to be colored 4a to 4c of the substrate 3.

  Specifically, for example, the color filter manufacturing apparatus includes a reading unit that reads the colored portions 4a to 4c of the substrate, and a distance between the two by moving the inkjet heads 2a to 2c and the substrate 3 relatively. The moving part which changes is provided.

  The reading unit includes, for example, a camera and a control unit, and transmits information (colored portion information) of the colored portions 4a to 4c photographed by the camera as data to the control portion.

  The control unit sets an optimum distance (optimum position) between the inkjet heads 2a to 2c and the substrate 3 based on the information of the colored parts 4a to 4c transmitted from the camera. Further, the control unit determines whether or not the pitch 6 between the colored portions 4a-4a of the same color and the pitch 16 between the central nozzles 1a-1a are different based on the information of the colored portions 4a to 4c. judge. And when this pitch differs, it sets so that the inkjet nozzles 2a-2c may incline as mentioned above.

  The moving unit relatively moves the inkjet heads 2a to 2c and the substrate 3 based on the optimum distance (optimum position) between the inkjet heads 2a to 2c and the substrate 3 set by the control unit. Further, when the control unit determines that the pitch is different, the moving unit moves the inkjet nozzles 2a to 2c so that the inkjet nozzles 2a to 2c are inclined as described above. The moving unit may move at least one of the substrate 3 and the inkjet heads 2a to 2c. That is, the moving unit may change the relative position between the inkjet heads 2 a to 2 c and the substrate 3. Note that the operation of moving the substrate relative to the inkjet heads 2a to 2c and the operation of adjusting the distance between the substrate 3 and the inkjet heads 2a to 2c may be performed by the same moving unit or by separate moving units. You may go.

  Examples of the moving unit include a stage that can move the substrate 3 in the xyz direction (three-dimensional direction). This stage can also be used for scanning the substrate 3 during ink ejection.

  According to the color filter manufacturing apparatus including the reading unit and the moving unit, the moving unit and the inkjet heads 2a to 2c (nozzles 1a to 1c) are connected to the colored portions 4a to 4c of the substrate 3 acquired by the reading unit. It is possible to set the angle and distance from the substrate 3 to an optimum position. Therefore, the intended ink landing positions 17 and 18 can be realized.

  As described above, the color filter manufacturing apparatus of the present embodiment has two or more nozzles 1a to 1c selected from the plurality of nozzles 1a to 1c (in the present embodiment, for one colored portion 4a to 4c). Ink is ejected simultaneously from three nozzles).

  The ink used for manufacturing the color filter has a higher viscosity than the ink used in a normal inkjet printer. For example, the ink used for manufacturing the color filter has a pigment component of 30% and a viscosity of 15 cP. For this reason, in a conventional color filter manufacturing apparatus, it is difficult for ink to spread over the entire portion to be colored. As a result, the manufactured color filter is likely to cause film thickness unevenness. A color filter with uneven film thickness cannot achieve highly accurate color reproducibility and brightness reproduction.

  On the other hand, in the color filter manufacturing apparatus according to the present embodiment, ink is ejected from the nozzle sets 1a to 1c to the colored portions 4a to 4c. Thereby, ink is landed on the to-be-colored parts 4a to 4c by a single ink discharge from the plurality of nozzles 1a to 1c. For this reason, ink can be ejected to a plurality of different points of the colored portions 4a to 4c by one ink ejection. As a result, for example, even when ink is ejected in the vicinity of the central portion of the colored portions 4a to 4c, the ink spreads not only in the vicinity of the central portion but also in the end direction of the colored portions 4a to 4c. Therefore, even when high-viscosity ink is used, it is possible to spread the ink over the entire colored portions 4a to 4c and manufacture a color filter with extremely small film thickness unevenness.

  Thereby, ink ejected from three nozzles adjacent to one colored portion can be landed near the center and near the end of the colored portion. Accordingly, it is possible to discharge ink uniformly in the width direction of the colored portions of the color filter (the arrangement direction of the colored portions). For this reason, after ink lands on the colored portion, the ink can be spread over the entire colored portion. Accordingly, since the ink spreads uniformly to the portion to be colored, it is possible to manufacture a color filter without unevenness in the ink (pigment) film thickness.

  In the configuration of Patent Document 2, when the nozzle pitch is the same or larger than the size of the pixel (colored portion), drawing can be performed using only one nozzle. In this case, when ink spread is taken into consideration, the ink is inevitably landed near the center of the pixel. For this reason, with the configuration of Patent Document 2, the landing position can be obtained only near the center of the pixel. Therefore, the ink cannot be spread in the direction perpendicular to the moving direction of the inkjet head.

  On the other hand, in the configuration of the present invention, ink droplets can be landed on a plurality of different points of the colored portions 4a to 4c by one ink ejection. For this reason, it is possible to spread the ink in a direction perpendicular to the moving direction of the inkjet head. Therefore, even if the viscosity of the ink to be ejected is high and the nozzle pitch is large with respect to the size of the pixel, if the ink is landed near the center, the ink does not spread and the ink does not spread over the entire pixel. Inconvenience can be solved.

  Furthermore, as a result of comparing the film thickness unevenness between the color filter manufactured by the method of this embodiment and the color filter manufactured by the method described in Patent Document 2, all the color filters manufactured by the method of this embodiment are It was 1% in the colored portion, and the ink spread throughout the colored portion, and it was confirmed that there was no portion where the ink did not spread.

  On the other hand, the film thickness unevenness of the color filter manufactured by the method of Patent Document 2 is about 5% over the entire substrate, and a portion where the ink does not spread over the entire colored portion was confirmed.

  The film thickness unevenness was evaluated by irradiating light from the back surface of the substrate to examine the distribution of transmitted light that passes through the color filter and from the transmitted light distribution. That is, light is applied from the back surface of the substrate and the amount of transmitted light is measured, and if the transmitted light is large, it is determined that the film thickness is thin, and if the transmitted light is small, the film thickness is determined to be thick. In this way, “film thickness unevenness” can be evaluated.

  In addition, when “film thickness unevenness” is large, a problem occurs in color reproducibility. The problem of color reproducibility also applies to a single color (in this embodiment, each color of red, blue, and green), and a combination of a plurality of colors (a color other than a single color), for example, superposition of red and blue This also applies if you can make purple. Therefore, for example, when making purple with a ratio of red to blue of 1: 1, for example, if there is a “film thickness unevenness” of + 5% in red, it appears to be a very reddish purple, and is a defective color filter. Become. The color filter of the present invention has a very small film thickness non-uniformity of 1% or less. Therefore, highly accurate color reproducibility and brightness reproducibility can be achieved not only for a single color but also for a combination of a plurality of colors. realizable.

  Note that the color filter manufacturing apparatus of the present embodiment can change at least the following points.

  In the present embodiment, as shown in FIG. 2, ink is ejected from the central nozzle 1 b and the two nozzles 1 b adjacent to the central nozzle 1 b to color one colored portion 4 b. That is, for each color, one colored portion 4a to 4c was colored using a nozzle set composed of three adjacent nozzles 1a to 1c. However, each nozzle 1a-1c of a nozzle set does not need to be adjacent. For example, a configuration may be adopted in which a plurality of nozzles to be used for each of the colored portions 4a to 4c are selected every other one. This is effective when the nozzle pitch 5 is narrower than the pixel width 7.

  Moreover, in this embodiment, three nozzles are made into one nozzle set about each nozzle 1a-1c. However, this nozzle set should just consist of two or more nozzles. That is, the number of nozzles in the nozzle set can be changed as appropriate. In this configuration, by increasing the number of nozzles constituting the nozzle set, it is possible to land the ink uniformly up to the end portions of the colored portions 4a to 4c. Accordingly, the ink spreads to the end portions of the colored portions 4a to 4c, and a color filter having a uniform film thickness can be manufactured.

  Further, the amount of ink ejected from one nozzle 1a to 1c can be suppressed. When the pixel width 7 of the colored portion 4a is large, it is preferable to increase the number of nozzles of the nozzle set. On the other hand, when the pixel width 7 is small, even if the amount of ink ejected from one nozzle 1a to 1c is reduced, the amount of ink increases if the number of nozzles in the nozzle set is large. For this reason, when the pixel width 7 of the colored part 4a is small, it is preferable to reduce the number of nozzle holes 8 to be used. Thereby, appropriate ink ejection according to the pixel width 7 becomes possible.

  In FIG. 4 and FIG. 5, each colored part 4a-4c is striped. However, a configuration may be employed in which the colored portions 4a to 4c are further finely separated to form pixels, and a plurality of pixels are arranged in a matrix.

  Banks (partitions) are formed between the portions to be colored 4 a to 4 c of the substrate 3 in order to prevent color mixing of different color inks. That is, each colored part 4a-4c is adjacent via the bank. This bank (partition) can be a black partition (black matrix) in order to prevent surface reflection of the colored portions 4a to 4c.

  The pixel width 7 and the pixel pitch 16 are not particularly limited because they vary depending on the size of the substrate 3 and the like. For example, when manufacturing a 45-inch WXGA type liquid crystal panel, in FIG. 4, the pixel width 7 per color is 242 μm, and the pixel pitch 16 is 729.3 μm. Banks (partition walls) are formed between the adjacent portions to be colored 4a to 4c in order to prevent ink color mixing. Here, since the bank width is about 3 μm, the pixel pitch 16 is not exactly three times the pixel width 7 per color.

  The substrate 3 may be appropriately selected depending on the purpose of use of the color filter, and is not particularly limited. As the substrate 3, for example, a glass substrate, a plastic substrate, a plate shape such as a plastic film, or a film shape can be used.

  In the present embodiment, the inkjet head 2 may be one in which the three color inkjet heads 2 a to 2 c are integrated, or may be a structure in which each inkjet head 2 a to 2 c is independent. If the inkjet heads 2a to 2c have independent structures, for example, when only one inkjet head is clogged with ink, only that inkjet head can be replaced.

  In addition, the manufacturing method and manufacturing apparatus of the color filter of this invention can also be expressed as follows.

  [1] The color filter manufacturing method of the present invention manufactures a color filter having a plurality of color elements (colored portions) by discharging ink from an inkjet head having a plurality of ink discharge nozzles at predetermined positions on a substrate. This is a color filter manufacturing method, and it can be said that when coloring the color element, a color pixel is formed using a plurality of nozzles for one pixel.

  In the formation of a conventional color filter, when the viscosity of the ink increases, the spread of the ink ejected to the pixel decreases, and after the ink is dried, the thickness of the ink in the pixel is not uniform, or the ink is applied to the entire pixel. There was a problem that it was not spread.

  Therefore, in the configuration [1], a color filter manufacturing method for manufacturing a color filter having a plurality of color elements by discharging ink from an inkjet head having a plurality of ink discharge nozzles at predetermined positions on a substrate. When coloring the color elements, the color pixels are formed by using a plurality of nozzles for one pixel, so that the pigment in the ink can be more uniformly arranged in the pixel after the ink is dried. That is, in the present invention, ink is ejected not only to the central part of the pixel but also to the end part of the pixel. For this reason, ink spreads over the whole pixel, and after the ink is dried, the thickness (film thickness) of the ink in the pixel can be made uniform. Furthermore, the optimal ink landing position can always be obtained for substrates of different sizes.

  [2] The plurality of nozzles described in [1] may be adjacent to each other. Thereby, the pigment | dye in an ink can be uniformly arrange | positioned in a pixel after drying of an ink more stably.

  [3] The plurality of nozzles described in [1] may be inclined in the center direction of the color pixel on the substrate or in the direction connecting the center of the nozzle hole and the center of the color pixel. Thereby, the pigment | dye in an ink can be uniformly arrange | positioned in a pixel after drying of an ink more stably.

  [4] The color filter manufacturing apparatus of the present invention includes a reading unit for reading the pixel size of the substrate, a moving unit capable of changing the distance between the substrate and the inkjet head, and a substrate obtained by the reading unit. From the size information, it can be said that the apparatus has means for moving the substrate or the ink jet head to an optimum position by the moving means.

  According to the above configuration, the landing position of the ink can be changed according to the size of the substrate of different sizes, and the pigment in the ink is more uniformly arranged in the pixel after the ink is dried. It becomes possible.

  [5] The color filter manufacturing apparatus according to the above [4] has means for moving the pitch between nozzles of the ink jet head to an optimum position with respect to the substrate from information on the size of the substrate obtained by the reading means. It may be.

  Thereby, the landing position of the ink can be changed according to the size of the substrate, and the pigment in the ink can be more uniformly arranged in the pixel after the ink is dried.

  [6] In the color filter manufacturing apparatus according to [5], the means for moving the nozzle-to-nozzle pitch of the inkjet head to an optimum position with respect to the substrate may rotate the inkjet head or the substrate.

  According to each of the above-described configurations, by rotating the inkjet head or the substrate as a means for moving the nozzle-to-nozzle pitch of the inkjet head to the optimum position with respect to the substrate, the coloring matter in the ink after drying the ink Can be more uniformly arranged in the pixels.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  According to the present invention, since a color filter without film thickness unevenness can be manufactured, various display panels having color filters can be applied to manufacturing.

It is a perspective view which shows the inkjet head in the color filter manufacturing apparatus of this invention. It is sectional drawing of the nozzle plate in the said inkjet head. It is a figure which shows the landing position of the ink in the said inkjet head. It is a figure explaining the manufacturing method of the color filter in case the said inkjet head is not inclined. It is a figure explaining the manufacturing method of a color filter in the case of making the said inkjet head incline. It is a figure explaining the manufacturing method of the conventional color filter.

Explanation of symbols

A Scanning direction 1a, 1b, 1c Nozzle 2, 2a, 2b, 2c Inkjet head 3 Substrate 4a, 4b, 4c Colored part 5 Nozzle pitch 6 Pixel pitch (Pitch between colored parts of the same color)
7 Pixel width 8 Nozzle hole 9 Ink landing position 11 Head chip 12 Piezoelectric element 13 Ink flow path 14 Tip 16 Pitch between center nozzles (pitch between nozzle sets of the same color)

Claims (9)

In a method for manufacturing a color filter that ejects ink by an inkjet method to a portion to be colored on a substrate,
A method for producing a color filter, comprising: a step of simultaneously ejecting ink from a nozzle set composed of two or more nozzles selected from a plurality of nozzles with respect to one colored portion.   The method for producing a color filter according to claim 1, wherein in the discharging step, adjacent nozzles are used as the nozzle set.   2. The method of manufacturing a color filter according to claim 1, wherein, in the ejection step, a nozzle having an ink ejection direction inclined toward a central portion of the colored portion is used as the nozzle set.   2. The method for manufacturing a color filter according to claim 1, wherein in the discharging step, the distance between the substrate and the nozzle is changed according to the size of the portion to be colored.   2. The discharge step includes changing the angle between the substrate and the nozzle so that a pitch between colored portions of the same color and a pitch between nozzle sets of the same color substantially coincide with each other. The manufacturing method of the color filter of description.   The method for manufacturing a color filter according to claim 5, wherein in the discharging step, the substrate or the nozzle is rotated. In a color filter manufacturing apparatus that ejects ink by an inkjet method to a plurality of colored portions on a substrate,
An apparatus for producing a color filter, comprising: a plurality of nozzles, and an inkjet head that simultaneously ejects ink from two or more nozzles selected from the plurality of nozzles with respect to one colored portion .   A color filter, wherein the uneven thickness of the colored portion is 1% or less.   A display panel comprising the color filter according to claim 8.

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