JP2010054777A - Forming method of thin film and color filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forming method of thin film capable of forming pixel areas of a color filter or the like onto a plurality of prescribed areas according to an inkjet method without forming a bank. <P>SOLUTION: The forming method of thin film comprises: a step of ejecting color filter ink 25 containing UV curable resin to a number of pixel areas which form patterns by using an inkjet recording head 30; a step of performing pinning P by irradiating the color filter ink 25 with UV rays 26 to temporarily cure a margin of the color filter ink 25 corresponding to each pixel area; and a step of primarily curing the color filter ink 25 by irradiating the color filter ink again with the UV rays 26 when the color filter ink 25 is flattened. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a thin film and a color filter, and is particularly useful when applied to the production of a color filter such as a liquid crystal by an ink jet method.

  As a method for producing a color filter used in a liquid crystal display device, a printing method, an electrodeposition method, a dyeing method, a pigment dispersion method, and the like are conventionally known. However, the printing method has a problem that the process is simple, but the flatness is inferior. The electrodeposition method has a problem that it is difficult to form a color array such as a mosaic pattern, and the dyeing method has a weather resistance. In addition, the pigment dispersion method has a problem that most of the used photosensitive resin is removed and discarded, and the utilization efficiency of the material is poor. .

  Thus, each conventional color filter manufacturing method has its own problems. In order to solve these problems, a method for manufacturing a color filter by an ink jet method has been proposed in recent years.

  The ink jet method is a color printing technique well known for so-called ink jet printers, and a pixel that is a colored layer of a color filter by discharging and fixing a large number of color filter ink droplets from an ink jet head onto a transparent substrate. A region is formed. According to the ink jet method, since the droplets of the color filter ink can be accurately ejected to a fine area, the color filter ink can be directly fixed to a desired pixel area without performing photolithography. Therefore, no waste of material occurs, the manufacturing cost can be reduced, and a very rational desired color filter can be manufactured.

  As a kind of color filter forming method by this type of ink jet method, a manufacturing method is proposed in which a bank which is a color filter ink receiving layer made of various polymers is provided on a transparent substrate, and the color filter ink is discharged and solidified in this bank. (For example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 2001-100022

  As described above, when an ink jet method is used in manufacturing a color filter, many advantages are obtained, but it is necessary to separately form a bank as a color filter ink receiving layer. The bank is usually formed by a lithography method. Therefore, the feature of the inkjet method proposed as an alternative in view of the problem that the lithography method forms the pixel region of the color filter is problematic in terms of cost. This is because even if the pixel region is formed by the ink jet method, the bank needs to be formed by the lithography method.

  On the other hand, when color filter ink is directly ejected onto a transparent substrate without forming a bank by the ink jet method, the color filter ink spreads at the peripheral portion and forms a pixel region in a predetermined region with high accuracy. It becomes difficult.

  In view of the above-described problems of the conventional technology, the present invention provides a thin film manufacturing method and a color filter capable of forming a pixel region such as a color filter in a predetermined plurality of regions by an inkjet method without forming a bank. With the goal.

  In order to achieve the above object, an embodiment of the present invention includes a step of ejecting a solution containing an ink containing an ultraviolet curable resin to a large number of regions forming a predetermined pattern by an inkjet printer, and irradiating the solution with ultraviolet rays. And a step of pre-curing and pinning the edge of the solution corresponding to each region, and a step of performing main curing by irradiating the solution with ultraviolet rays again when the solution is flattened. There is a method for manufacturing a thin film.

  According to this aspect, the solvent of the solution is evaporated in a state where the solution is temporarily cured and the edge portion is pinned (referred to as fixing the position of the edge portion by temporarily curing the solution; hereinafter the same). Since a typical thin film can be formed, even if there is no bank, the thin film can be formed in a predetermined region with a predetermined accuracy without causing loss of shape or bleeding in the middle.

  The solvent is evaporated in a state where the edge of the solution is pinned, and finally hardened by ultraviolet irradiation. As a result, a uniform level is maintained in the process of flattening the solution by evaporation of the solvent. Therefore, the solution that has been fully cured in this state has a good leveling property, and can contribute to the improvement of the uniformity of the film thickness of the thin film and the improvement of the quality of the liquid crystal device to which this is applied.

  Here, after pinning the solution, the solution may be heated and then re-irradiated with ultraviolet rays. In this case, since the evaporation of the solvent can be promoted by heating, the production time can be shortened. Moreover, after pinning the solution, the solution may be heated to perform main curing. In this case, the same effect is obtained. In addition, the solution in this case shall have a function of ultraviolet curing and thermal curing due to its structure. Further, the ejection of the solution by the ink jet printer may be performed a plurality of times for each region, and a step of temporarily curing and pinning the edge of the solution every time the ejection of the solution is completed may be provided. In this case, a thin film having an arbitrary thickness can be manufactured satisfactorily.

  Furthermore, the thin film may be formed in the pixel region of the color filter. As a result, the pixel region of the color filter can be formed by an inkjet method and without requiring a bank.

  Another aspect of the present invention is a color filter manufactured by the method for manufacturing a thin film. Such a color filter does not require a bank and can be manufactured at low cost. Moreover, the shape of the edge of the pixel region is not broken.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing a liquid crystal display device which is an example of a device having a color filter manufactured by the color filter manufacturing method according to the present embodiment. The liquid crystal display device 1 shown in FIG. 1 includes a TFT array substrate 4 in which pixel electrodes 2 and thin film transistors 3 (Thin Film Transistors; hereinafter abbreviated as TFTs) that are switching elements of the pixel electrodes 2 are arranged in a matrix, A pixel region 5 corresponding to each of the R, G, and B pixel regions has a color filter 6 arranged in a desired color arrangement pattern and a counter substrate 8 provided with a counter electrode 7.

  Here, in each pixel area 9 defined by the pixel electrode 2 on the TFT array substrate 4 and each pixel area 5 of the color filter 6, all of the horizontal dimension, the vertical dimension, and the dimension between adjacent areas are set to be the same. The two regions 5 and 9 are aligned so as to correspond to each other.

  In the counter substrate 8, the color filter 6 is formed on the upper surface of the transparent substrate 22 similar to the TFT array substrate 4 side. In the color filter 6, R, G, and B pixel regions 5 are partitioned in a lattice pattern, and a light-shielding layer that shields light between the pixel regions 5, a so-called black matrix 23, is formed on the transparent substrate 22. Each pixel is formed by fixing the color filter inks of R, G, and B in the region 5.

  A counter electrode 7 made of a transparent conductive film such as ITO is formed on the entire surface of the color filter 6. Further, an alignment film (not shown) made of polyimide or the like is also formed on the counter substrate 8 side.

  A method for manufacturing the color filter 6 of the liquid crystal display device will be described in detail with reference to FIG.

  First, as shown in FIG. 2A, a color filter ink 25, which is a kind of liquid containing an ultraviolet curable resin, is applied to a pixel region on a glass transparent substrate 22 on which a black matrix 23 is formed. 30. The color filter ink 25 contains a trace amount of an ultraviolet curable resin composed of a curing initiator and a monomer. Here, the color filter ink 25 ejected to the pixel region is irradiated with ultraviolet rays 26, and the edge portion thereof is temporarily cured and pinned (the pinning portion is given the symbol “P” in the figure; the same applies hereinafter). ) This pinning may be performed at the timing when the color filter ink 25 is ejected in the state where the ultraviolet ray 26 is irradiated, or may be immediately after the ejection. In short, it is only necessary that the color filter ink 25 is wet and moves, and the color filter ink 25 can be prevented from flowing out to an area beyond the edge of the pixel area.

  Further, pinning can be performed by selectively irradiating the edge of the color filter ink 25 with ultraviolet rays. In this case, since necessary portions are selectively pinned, provisional curing is also limited.

  As shown in FIG. 2B, when the color filter ink 25 is separately applied to a plurality of layers in the formation of the pixel region, the same process as in FIG. 2A is repeated. That is, the upper color filter ink 25 is ejected onto the lower color filter ink 25 to pin the edge. By repeating this process as many times as necessary, a pixel region having a desired film thickness is formed.

  Although there is no particular limitation on the type of the ink jet printer used in the steps of FIGS. 2A and 2B, an example will be described with reference to FIG. As shown in the drawing, the ink jet recording head 30 includes a pressure generation chamber 33 that communicates with a nozzle opening 32 that ejects color filter ink, and a flow path 34 that communicates the pressure generation chamber 33 with an ink cartridge (not shown). A vibration plate 35 provided to face the pressure generation chamber 33 and a piezoelectric element 31 for generating a pressure change in the pressure generation chamber 33 via the vibration plate 35 are provided. The piezoelectric element 31 is fixed to the case 36 via a fixing plate 37. In the vicinity of the base end portion of the piezoelectric element 31, wiring 38 for supplying a drive signal for driving each piezoelectric element 31 is provided on the surface opposite to the fixed plate 37. This wiring 38 is connected to a head controller (not shown).

  In the ink jet recording head 30, a driving signal is sent from the head control unit to the ink jet recording head 30 via the wiring 38, and the driving signal is applied to the piezoelectric element 31. The piezoelectric element 31 changes the volume of the pressure generating chamber 33 by deforming the diaphragm 35 by repeatedly expanding and contracting by repeatedly charging and discharging according to the drive signal. Due to the change in volume of the pressure generating chamber 33, color filter ink droplets are ejected from the predetermined nozzle openings 32.

  The color filter ink 25 ejected from the ink jet recording head 30 in the step shown in FIG. 2B is pinned at the edge thereof, and the central portion rises due to the surface tension. The solvent of the color filter ink 25 is evaporated by heating in a heating furnace (not shown). Here, in the color filter ink 25, the evaporation of the solvent proceeds in a state where the position of the edge is regulated by the pinning. As a result, a uniform film thickness level is maintained in the process of flattening the color filter ink 25 by evaporation of the solvent.

  Such a heating step is not always necessary. In some cases, planarization may be performed by evaporating the solvent by natural drying.

  Finally, as shown in FIG. 2 (c), the color filter ink 25 is irradiated with ultraviolet rays again in a state where the color filter ink 25 in each pixel region is flattened to be fully cured.

  Thus, the finally cured color filter ink has a good leveling property, and can contribute to the improvement of the performance of the color filter and the improvement of the quality of the liquid crystal device to which this is applied.

  If the solution such as the color filter ink has both the properties of ultraviolet curing and heat curing, after the solution is pinned, the solution may be heated to perform the main curing. In this case, the same effect as that obtained when the main curing is performed by ultraviolet curing is obtained. As the solution, in addition to the color filter ink 25, an ink containing an organic EL light emitting layer, an ink containing a conductive component such as silver, or the like can be used.

  Further, although the above embodiment has been described as a method for manufacturing a color filter, the present invention is not limited to this. In general, the present invention can be applied to a case where a large number of regions for forming a predetermined pattern are manufactured using ink jet printing.

It is a schematic block diagram which shows the liquid crystal display device which has a color filter. It is explanatory drawing which shows each process of the manufacturing method of the color filter which concerns on embodiment. 1 is a schematic configuration diagram illustrating an example of an ink jet recording head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 5 Pixel area | region 6 Color filter 22 Transparent substrate 25 Color filter ink 26 Ultraviolet ray 30 Inkjet recording head

Claims (6)

Discharging a solution containing an ink containing an ultraviolet curable resin to a large number of regions forming a predetermined pattern by an inkjet printer;
Irradiating the solution with ultraviolet light to temporarily cure the edge of the solution corresponding to each region and pinning;
A method of producing a thin film, comprising the step of irradiating the solution again with ultraviolet rays and performing main curing when the solution is flattened. In the manufacturing method of the thin film of Claim 1,
A method for producing a thin film, comprising: pinning the solution, heating the solution, and then performing re-irradiation with ultraviolet rays. In the manufacturing method of the thin film of Claim 1,
After pinning the solution, the solution is heated to perform main curing. In the manufacturing method of the thin film of Claim 1 or Claim 2,
A method for producing a thin film, comprising: performing ejection of the solution by an ink jet printer a plurality of times for each region, and performing pinning by temporarily curing an edge of the solution every time the ejection of the solution is completed. In the manufacturing method of the thin film as described in any one of Claim 1 thru | or 4,
The method for producing a thin film, wherein the thin film is formed in a pixel region of a color filter. A color filter manufactured by the method for manufacturing a thin film according to any one of claims 1 to 5.

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