JPH0894822A - Liquid crystal color filter manufacturing method and intaglio used for the same - Google Patents

Abstract

(57) [Abstract] [Purpose] A method for producing a liquid crystal color filter having a pattern shape of a transparent colored layer and good surface flatness,
Provide the intaglio used for this. [Constitution] At least a surface of the intaglio plate 1 made of silicone rubber is used, ink is filled in the recesses 3 formed on the surface printing layer 2, and then the ink is directly transferred onto the transparent substrate 6 to form the transparent coloring layer 7. Let it form. The intaglio 1 may be one in which the surface printing layer 2 is formed on the support 4 directly or via a foam layer. [Effect] Since the ink is directly transferred from the intaglio having a silicone rubber having a high ink releasability on the surface, the ink is completely transferred, and the liquid crystal is excellent in the shape of the pattern of the transparent colored layer and the flatness of the surface. A color filter is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a liquid crystal color filter used in a liquid crystal color display and an intaglio plate used for the method.

[0002]

2. Description of the Related Art A liquid crystal display (LCD), which is a typical flat panel display, has features such as light weight, thin shape, and power saving, and is used as a display device replacing a conventional cathode ray tube (CRT). It is used in many fields such as, personal computer, electronic desk calculator, clock, and television.

The color display of a liquid crystal display is a liquid crystal color in which a transparent colored layer consisting of patterned red (R) color, green (G) color and blue (B) color layers is formed on a transparent substrate such as glass. It is realized by using a filter. The transparent colored layer has a great influence on the image quality such as causing color unevenness in the image quality of the liquid crystal color display, and therefore the surface flatness and pattern precision are required.

Conventionally, a photolithography method has been used to form such a transparent colored layer. However, this method requires a high cost, which makes the liquid crystal color filter expensive, which causes a rise in the price of the liquid crystal color display. ing. Therefore, in order to manufacture an inexpensive liquid crystal color filter, it is considered to use a printing method having a simple process for forming the transparent colored layer. However, in printing methods such as waterless lithographic offset printing and intaglio offset printing, the ink is divided into a transfer body and a non-transfer body during transfer, and a part of the ink remains untransferred on the non-transfer body. For this reason, in the transparent colored layer formed by such a printing method, the shape of the pattern is changed due to chipping of the edge portion or the surface of the pattern is uneven.

On the other hand, since silicone rubber has a good releasability of ink, a printing method has been proposed in which the surface printing layer uses an offset blanket made of silicone rubber to prevent the ink from splitting (Japanese Patent Laid-Open No. Sho 61-242, 1988). 62-852
No. 02). However, the ink is divided during the transfer process from the plate such as the intaglio plate or the planographic plate to the blanket, and the ink cannot be completely transferred (complete transfer). Therefore, it is necessary to prevent the ink from being divided during the transfer from the intaglio plate or the lithographic plate to the blanket.

Therefore, the inventors of the present invention previously tried to completely transfer the ink to the offset blanket using an intaglio coated with silicone or fluororesin having a low surface tension on the inner surface of the indented plate. It was very difficult to apply a uniform coating to the inside, and the ink was partially left in the recesses even after the coating, so that the complete transfer of the ink could not be realized.

The object of the present invention is to provide a method for producing a liquid crystal color filter which prevents the ink from splitting during printing, has a good pattern shape of the transparent colored layer, and has excellent surface flatness, and a method for producing the same. To provide an intaglio.

[0008]

The present inventors have found that the silicone rubber used for the surface printing layer of the offset blanket is a non-adhesive material and therefore has excellent ink releasability. The present invention has been completed by discovering the fact that printing can be performed very simply and without ink splitting if an offset blanket made of rubber itself has a plate function.

That is, the method for producing a liquid crystal color filter of the present invention is characterized in that the concave portion of the intaglio plate made of silicone rubber is filled with ink, and then this ink is directly transferred onto the transparent substrate to form a transparent colored layer. And The intaglio plate of the present invention is characterized in that at least the surface is made of silicone rubber.

The present invention will be described in detail below. At least the surface of the intaglio plate of the present invention is made of silicone rubber. Such an intaglio may be made of only silicone rubber, but in order to prevent the elongation of the silicone rubber, it is preferable to form a surface printing layer made of silicone rubber on the support directly or through a foam layer. .

As the silicone rubber, dimethyl type (MQ), methyl vinyl type (VMQ), methylphenyl vinyl type (PVMQ), methyl fluoroalkyl type (FV).
One of the main components is silicone raw rubber such as MQ). Millable silicone rubber that can be kneaded, RTV (RoomTe
Various known forms such as mperature Vulcanizing) silicone rubber and LIM (Liquid Injection Molding) silicone rubber capable of injection molding can be used.

Also, by mixing short fibers in the silicone rubber,
Those reinforced in strength can also be used. Short fibers mixed in
Examples of fibers include polyester short fibers and nylon short fibers.
Fiber, natural cellulose short fiber, etc.
It is used after being surface-treated with a run coupling agent or the like. Shi
The amount of short fibers mixed in the silicone rubber is
10 to 200 parts by weight per 100 parts by weight, more preferred
Specifically, it is 30 to 100 parts by weight, and the strength of rubber (tensile strength
JIS K 6301) is 50-150 kg weight / cm ²,Than
Preferably 100-150 kg weight / cm²Will be in the range of
To adjust.

Incidentally, the intaglio plate made of silicone rubber may deform the intaglio plate itself. In order to suppress such deformation, the hardness of the silicone rubber may be increased, and the hardness (JIS K 6301 A) is 40 to 90 degrees, more preferably 70 to 90 degrees. As a method for forming the concave portion of the intaglio, for example, there is a method of pouring a liquid silicone rubber into a master having a pattern of the concave and releasing the cured rubber from the master. As the master, for example, glass is used, and a pattern is formed on the master by etching.

The depth of the recess of the intaglio plate is 30 μm or less, preferably 2 to 15 μm. Since the intaglio plate made of only silicone rubber tends to extend in the printing tensile direction, it is preferable that the surface printing layer 2 made of silicone rubber is formed on the support 4, as shown in FIG.
Further, as shown in FIG. 2, the surface printing layer 2 may be formed on the support 4 via the foam layer 5.

The foam layer means a porous rubber layer and is classified into a closed cell type and an open cell type. In the case of the closed cell type, it is obtained by mixing a foaming agent into rubber and foaming simultaneously with vulcanization. On the other hand, in the case of the open-cell type, it can be obtained by mixing an organic salt or an inorganic salt into rubber, vulcanizing and extracting. By providing such a foam layer 5, there are advantages that the printing dimensional accuracy is improved, and fluctuations in the printing pressure due to variations in the thickness of the glass printing medium are reduced.

The intaglio plate used in the present invention is not limited to the structure shown in FIGS. 1 and 2, and may be, for example, an ordinary offset blanket whose surface is made of silicone rubber, in which concave parts are formed. However, it can be preferably used. Examples of the support include polyethylene terephthalate (PET) film, polycarbonate (PC) film, polyether sulfone (PE)
S) Film, etc., and if more strict dimensional accuracy is required, use a woven or non-woven fabric made of high-strength aramid fiber impregnated with a resin, or use a thin metal plate such as aluminum or stainless steel. Can be used. The thickness of the support is 10 to 2000 μm, more preferably 50 to 500 μm.

The foam layer is not particularly limited. For example, a layer obtained by mixing inorganic salt or the like in rubber and extracting it with warm water after vulcanization, or a foaming agent in rubber and foaming at the time of heating and vulcanization. It can be used. The thickness of the foam layer is
50 to 1000 μm, more preferably 200 to 500 μm
m. In the method for producing a liquid crystal color filter of the present invention, ink is directly printed on a transparent substrate to form a transparent colored layer using the intaglio plate described above.

The ink is not particularly limited,
Any ink resin may be used as long as it is an ink resin that sufficiently satisfies the characteristics of the transparent colored layer of the liquid crystal color filter. For example, heat-curable ink, ultraviolet-curable ink (UV ink), electron beam-curable ink (EB ink), infrared-curable ink (IR ink), etc. can be used, and each of them is mixed with a predetermined colorant. Adjust red, green, and blue ink.

The thermosetting ink is colored with an epoxy resin (such as bisphenol A type), a melamine resin (such as methylated melamine), an acrylic resin, a urethane resin, a polyimide resin, a polyester resin, or a mixture of two or more thereof. It is prepared by mixing agents and solvents. In this case, a melamine resin is often used as a curing agent, and in particular, there are many combinations of epoxy-melamine (curing agent) and polyester-melamine (curing agent). Further, an acid catalyst (usually p-toluenesulfonic acid) may be added in a proportion of 0.1 to 0.5% by weight to the resin for the purpose of lowering the curing temperature. Thereby, the curing temperature is 10 to 30
C can be reduced.

The UV-curable ink is prepared by mixing a photo-curable acrylic group-containing monomer with an oligomer having a relatively large molecular weight to adjust the viscosity, adding benzophenone as a sensitizer, and finally adding a pigment. It is created by mixing The ink used preferably has a low viscosity as described above, and specifically has a viscosity of 10 to 30,0.
Suitably it is 00P, preferably 500-10,000P.

A pigment is mainly used as a colorant to be added to the above ink, and is selected in consideration of various characteristics such as heat resistance and light resistance. For example, as the colorant for red color, dianthraquinone type, perylene type, condensed azo type, quinacridone type, etc., as the colorant for green color, chlorinated phthalocyanine copper,
Examples include brominated copper phthalocyanine, and examples of the blue colorant include phthalocyanine copper.

As the transparent substrate of the liquid crystal color filter, for example, non-alkali glass, soda lime glass,
Low alkali glass can be used. The transparent colored layer is formed, for example, as follows. First, the intaglio plate of the present invention is filled with ink. As a method of filling the ink, a conventionally known method such as a method of filling the concave portion with a squeegee or a method of scraping off excess ink with a doctor can be used. Then, the ink is directly transferred from the intaglio plate filled with the ink onto the transparent substrate for printing.

Since one color of the transparent colored layer is formed by the above printing, the above steps are repeated depending on the number of colors of the transparent colored layer. After printing, the ink transferred onto the transparent substrate is heated and cured at a temperature at which the transparent substrate is not thermally deformed, usually at 180 to 250 ° C. for 30 to 180 minutes, and more preferably at 200 to 230 ° C. for 50 to 80 minutes.

The thickness of the transparent colored layer is limited by the depth of the concave portions of the intaglio plate, but is preferably in the range of 1 to 5 μm, more preferably 2 to 3 μm. The liquid crystal color filter obtained by the present invention has a transparent colored layer 7 (7R) having a pattern of red (R), green (G) and blue (B) on a transparent substrate 6, as shown in an example in FIG. , 7G,
7B) has been formed.

[0025]

EXAMPLES Examples of the present invention will be described below. Example 1 The intaglio used was one in which a surface printing layer made of silicone rubber was formed on a support.

For the surface printing layer, a composition (KE-1300 manufactured by Shin-Etsu Chemical Co., Ltd.) in which a raw silicone raw rubber is mixed with a cross-linking agent and the like is poured into a master and allowed to stand at room temperature. I got it by patterning. On the surface of the obtained surface printing layer, a recess having a line width of 100 μm and a depth of 6 μm was formed. The thickness of the surface printing layer is 0.5.
mm, the hardness of silicone rubber is (JIS K 6301 A) 50
It is degree.

Next, the surface printing layer has a thickness of 0.3.
An intaglio plate was obtained by adhering it onto a support made of a polyethylene terephthalate (PET) film having a thickness of mm. The transparent colored layer consists of three colors, red, green and blue. The intaglio plate was attached to the plate cylinder of a printing machine (Ektor made by Koyosha Co., Ltd.), the ink was embedded in the intaglio plate with a squeegee, and the transparent substrate was made of soda lime glass. It was formed by direct printing on and then heating and curing the ink at 220 ° C. for 60 minutes.

As the ink, a thermosetting polyester resin (manufactured by Sumitomo Rubber Industries, Ltd.) and a transparent pigment dissolved in a higher alcohol were used. For the transparent pigment, anthraquinone was used as red, chlorinated phthalocyanine copper was used as green, and phthalocyanine copper was used as blue. During the printing of the transparent colored layer, the ink in the intaglio depression was completely transferred, and the ink did not split even after continuous printing of 10,000 times. Example 2 The intaglio plate used is one in which a surface printing layer made of silicone rubber is formed on a support through a foam layer.

The surface printing layer was obtained in the same manner as in Example 1. The thickness of the obtained surface printing layer is 0.7 mm. The hardness of the surface printing layer (JIS K 6301 A) and the line width and depth of the recess are the same as in Example 1. Then, the surface printing layer is adhered onto a foam layer having a thickness of 0.2 mm, and a thickness of 0.
An intaglio plate was obtained by adhering it onto a support made of a 1 mm aluminum film.

As the foam layer, a layer obtained by mixing a silicone rubber with a foaming agent to foam [foaming rate 50% (volume ratio)] was used. Further, in the same manner as in Example 1, the intaglio plate was attached to a plate cylinder of a printing machine, ink was directly printed on a transparent substrate to print, and the ink was heated and cured to form a transparent colored layer.

During the printing of the transparent colored layer, the ink in the intaglio depression was completely transferred, and the ink did not split even after continuous printing of 10,000 times. In addition, the silicone rubber showed almost no elongation and the dimensional accuracy of printing was extremely good. Example 3 The intaglio used was one in which a surface printing layer made of silicone rubber was formed on a support.

The surface printing layer was obtained in the same manner as in Example 1. Hardness of the intaglio of the obtained surface printing layer (JIS K 6301 A)
Is 70 degrees. The thickness of the surface printing layer and the line width and depth of the recess are the same as in Example 1. When kneading the silicone raw rubber which is the base of the surface printing layer, aramid short fibers (Technora manufactured by Teijin Ltd.) surface-treated with a silane coupling agent are added to improve the strength.

Next, the surface printing layer is formed to have a thickness of 0.3.
An intaglio plate was obtained by adhering it onto a support made of a stainless steel film of mm. Foam layer (thickness 0.2 mm)
Adhere on top, aluminum film (thickness 0.1m
m) was formed on a support. Furthermore, Example 1
Similarly to the above, the intaglio plate was attached to a plate cylinder of a printing machine, ink was directly printed on a transparent substrate, and the ink was heated and cured to form a transparent colored layer.

During the printing of the transparent colored layer, the ink in the intaglio depression was completely transferred, and the ink did not split even after continuous printing of 10,000 times. In addition, the silicone rubber showed almost no elongation and the dimensional accuracy of printing was extremely good. Comparative Example 1 Using a waterless planographic printing plate and a blanket made of acrylonitrile butadiene rubber (NBR) [ST 800 manufactured by Sumitomo Rubber Industries, Ltd.] on the surface, a line width of 100 μm was formed on a soda lime glass substrate by a waterless planographic printing method. To form a transparent colored layer having a stripe pattern. The same glass substrate and ink as those used in Example 1 were used. Further, since the ink film of the transparent colored layer by this method was insufficient, overprinting was performed 5 times so as to obtain a predetermined thickness (1.5 μm).

During the printing of the transparent colored layer, the transfer from the lithographic plate to the blanket and the transfer from the blanket to the substrate are performed.
The ink has split over time. As a result, the obtained liquid crystal color filter had uneven color. Comparative Example 2 Using a glass intaglio having a pattern with a line width of 100 μm and a plate depth of 8 μm and a blanket (manufactured by Sumitomo Rubber Industries, Ltd.) having a surface portion made of silicone rubber, soda lime glass by an intaglio offset printing method. A transparent colored layer was formed on the substrate. The glass substrate and the ink are used in Example 1.
The same as that used for was used.

During the printing of the transparent colored layer, the ink in the intaglio depression did not break during the transfer from the blanket to the substrate, but did split during the transfer from the intaglio to the blanket. Although the obtained liquid crystal color filter had little color unevenness,
About 15% reduction in the thickness of the ink film was observed between the initial printing result and the 10,000th printing result when continuous printing was performed 10,000 times. Comparative Example 3 An intaglio plate made of glass in which a silicone resin (KE347 manufactured by Shin-Etsu Chemical Co., Ltd.) was coated by a dipping method on the concave part of a glass intaglio plate having a pattern with a line width of 100 μm and a plate depth of 8 μm, and a surface portion. A transparent colored layer was formed on a soda lime glass substrate by an intaglio offset printing method using a blanket (manufactured by Sumitomo Rubber Industries, Ltd.) made of silicone rubber. The same glass substrate and ink as those used in Example 1 were used.

When the transparent colored layer was printed, the ink in the intaglio depression did not split during the transfer from the blanket to the substrate, so the resulting liquid crystal color filter had little color unevenness. In addition, when continuous printing was performed 10,000 times, ink division was not observed in the transfer from the intaglio plate to the blanket in the initial printing, but the coating part of the intaglio concave part peeled or swelled at the 1000th to 5000th times, Partially ink splitting occurred and color unevenness appeared.

[0038]

EFFECTS OF THE INVENTION According to the present invention, since the surface printing layer of the intaglio plate is made of a silicone rubber having excellent releasability of ink, and the direct printing method is adopted in which the ink is directly transferred from the intaglio plate to the transparent substrate. , The ink does not break when transferring the ink onto the transparent substrate. Furthermore, it is possible to obtain a liquid crystal color filter having a transparent printed layer having a flat print pattern and a good print pattern shape.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an intaglio plate of the present invention.

FIG. 2 is a schematic view showing an example of an intaglio plate of the present invention.

FIG. 3 is a schematic view showing an example of a liquid crystal color filter obtained by the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Intaglio 2 Surface printing layer 3 Recesses 4 Support 5 Foaming layer 6 Transparent substrate 7 Transparent colored layer

Claims (3)

[Claims] 1. A method for producing a liquid crystal color filter, which comprises filling a concave portion of an intaglio plate made of silicone rubber with ink and then directly transferring the ink onto a transparent substrate to form a transparent colored layer. 2. An intaglio plate, at least the surface of which is made of silicone rubber. 3. The surface printing layer made of silicone rubber is formed on the support directly or through a foam layer.
The intaglio described.