TWI412795B - Method for manufacturing color filter - Google Patents

Abstract

A method for manufacturing color filter includes steps of forming a transparent-matrix on a flexible and transparent substrate for dividing the substrate to plurality of pixel areas; printing the plurality of pixel areas with ink by using an inkjet printing process; and curing the ink. The light transmittance ability of the color filter can be effectively improved by forming the transparent-matrix on the substrate instead of black-matrix.

Description

Color filter manufacturing method

The present invention relates to a method of fabricating a color filter, and more particularly to a method of fabricating a color filter having a flexible substrate.

In recent years, e-books have been favored by more and more readers. E-books are reflective electronic paper displays. Reflective electronic paper has the advantages of no backlight, no eye damage, and steady-state display. The existing reflective electronic paper includes electrophoretic electronic paper, cholesteric liquid crystal electronic paper, electrowetting electronic paper, and the like. The electrophoresis type electronic paper adopts a microcapsule structure, and the microcapsule is encapsulated with an electrophoresis liquid, and two electrophoretic liquids are suspended in two kinds of electrophoretic particles with opposite charges in black and white. The two electrophoretic particles are in the microcapsule under the action of an electric field. Migrate between the top and bottom to achieve color switching. If electrophoretic electronic paper is developed into color electronic paper, in principle, there are two different ways to achieve it. The first one can replace the white particles with colored particles (RGB/YMC), and then mix colors by the color particle mixing principle. The color display is realized; the other is to increase the color filter structure on the black and white electronic paper to make the electronic paper full-color display.

For the method of adding a color filter structure to an electronic paper, a method of forming a color filter by inkjet printing has been developed in recent years. The method first forms a black matrix on a glass substrate to define a plurality of primitive regions. Of course Thereafter, an inkjet printing process is performed to inject pigment inks (red, green, and blue) into the primitive regions defined by the black matrix. A thermal baking process is then performed to cure the pigment. Forming a black matrix on a glass substrate generally employs the following method of coating a photosensitive resin on a substrate, prebaking the photosensitive resin composition to form a black matrix film, and then selectively exposing and developing the black matrix film, and then performing bake.

Since the electronic paper is soft, when the glass substrate filter produced by such a method is laminated with the electronic paper, there is a problem that the bonding of the air bubbles or the like is poor. The above method of forming a color filter by inkjet printing is not suitable for forming a color filter on a flexible plastic substrate, and curing of the pigment and formation of a black matrix require a hot baking process. Flexible plastic substrates generally do not have the characteristics of high temperature resistance.

In view of this, the present invention provides a flexible filter and a method of forming a color filter on a flexible substrate.

A method of manufacturing a color filter, the method comprising the steps of: providing a flexible transparent substrate, forming a transparent matrix on the transparent substrate, the transparent matrix dividing a plurality of primitive regions on the transparent substrate, The transparent matrix has different surface wettability with the primitive region, the transparent matrix exhibits hydrophobicity, and the primitive region exhibits hydrophilicity. The pigment ink is applied in a plurality of element regions by an inkjet printing method to cure the pigment ink to form a plurality of color filter films.

The invention does not need to form a black matrix on the substrate, but instead forms a transparent matrix directly on the transparent substrate, and the transparent matrix is used to increase the transmittance of the filter. The invention adopts The color filter manufactured by using a flexible transparent substrate can be well bonded to the electronic paper without causing problems such as poor bonding of bubbles or the like. The curing of the pigment does not require a hot baking process, and the curing of the pigment ink by low-temperature heat curing or ultraviolet (UV) curing does not adversely affect a flexible substrate that does not have heat resistance.

S301, S302, S303, S3011, S3012, S3013, S3014‧‧ steps

11, 12‧‧‧ Transparent substrate

111, 121‧‧‧ element area

112, 122‧‧‧transparent matrix

21, 22‧‧‧ hood

211‧‧‧Transparent area

212‧‧‧Light blocking zone

31, 32‧‧‧ nozzle

41, 42‧‧‧ pigment ink

411, 421‧‧‧ red pigment ink

412, 422‧‧‧Green pigment ink

413, 423‧‧‧Blue pigment ink

51, 52‧‧‧ ultraviolet light source

60‧‧‧Photosensitive materials

70‧‧‧electronic paper

71‧‧‧Substrate

72‧‧‧Electronic paper body

73‧‧‧Filter

721‧‧‧First electrode

722‧‧‧second electrode

723‧‧‧electrophoretic layer

1 is a flow chart of a method of fabricating a color filter having a flexible substrate in accordance with a preferred embodiment of the present invention.

FIG. 2 is a sub-flowchart of step S301 in the first embodiment of the present invention.

3 is a schematic view showing a manufacturing process of a color filter having a flexible substrate in the first embodiment of the present invention.

4 is a schematic structural view of a hood according to a first embodiment of the present invention.

FIG. 5 is a sub-flowchart of step S301 in the second embodiment of the present invention.

6 is a schematic view showing a manufacturing process of a color filter having a flexible substrate in a second embodiment of the present invention.

Fig. 7 is a schematic view showing the structure of a reflective electronic paper having a flexible filter.

1 is a flow chart of a method of fabricating the color filter having a flexible substrate in accordance with a preferred embodiment of the present invention. The method includes the steps of: step S301, forming a transparent matrix on a transparent substrate, the transparent matrix dividing a plurality of primitive regions on the transparent substrate, the transparent matrix and the primitive region having different surface wettability; S302, applying pigment ink in a plurality of primitive regions by using an inkjet printing method, wherein the inkjet printing method is used, and the pigment ink is used by a nozzle (red pigment ink, green) The color pigment ink and the blue pigment ink are positioned and coated in the pixel region; in step S303, the pigment ink is cured to form a plurality of color filter films, wherein the transparent substrate on which the pigment ink has been coated is specifically exposed to the ultraviolet light source.

Referring to FIG. 2 and FIG. 3 together, FIG. 2 is a sub-flow chart of step S301 in the first embodiment of the present invention, and FIG. 3 is a schematic diagram of a manufacturing process of the color filter having a flexible substrate in the first embodiment of the present invention. . In the first embodiment of the present invention, step S301 includes the steps of:

In step S3011, the transparent substrate 10 is placed in a carbon tetrafluoride (CF4) gas.

Referring to FIG. 3a, the transparent substrate 11 is made of a flexible plastic having high light transmittance, and may be polyisoprene (PI), polycarbonate (PC), or polyethylene terephthalate (PET). A transparent plastic material such as polymethyl methacrylate (PMMA). In the present embodiment, the flexible plastic is preferably a polycarbonate (PC) material. The transparent substrate 11 is placed in a carbon tetrafluoride (CF4) gas.

In step S3012, the transparent substrate 11 is exposed to light by the hood 21. Referring to FIG. 4 together, the hood 21 includes a light transmitting region 211 and a light blocking region 212. The light transmitting region 211 has a matrix pattern, and the light blocking region 212 is a plurality of discrete rectangular regions. The hood 21 is placed on the transparent substrate 11, and the light can pass through the transparent region 211. In the CF4 atmosphere, the surface of the transparent substrate 11 that is not shielded by the hood 21 is subjected to photocatalysis to cause plasma penetration, and the surface region passes through. Plasma penetration, its surface energy is reduced, and hydrophobicity is enhanced. After the transparent substrate 11 is exposed, the surface of the transparent substrate 11 that is not shielded by the hood 21 forms a transparent matrix 112 that divides the transparent substrate 11 into a plurality of primitive regions 111.

The transparent matrix 112 has different surface wettability from the primitive region 111. In the present embodiment, the transparent matrix 112 exhibits hydrophobicity, and the primitive region 111 exhibits hydrophilicity. Generally, the hydrophilicity and hydrophobicity of the material are defined by the wetting angle, and the material having a wetting angle of 90° is a hydrophilic material. Materials with a wetting angle > 90° are hydrophobic materials. In the present invention, the wetttage angle of the transparent matrix 112 and the primitive region 111 differs by 10. In the above embodiment, the wetting angle of the transparent matrix 112 and the primitive region 111 is selected to be 50° or more.

Referring to FIG. 3b, in the embodiment, step S302 is specifically: using the inkjet printing method, the pigment ink 41 (the red pigment ink 411, the green pigment ink 412, and the blue pigment ink 413) is positioned and applied by the nozzle 31. In the primitive area 111. Since the surface of the primitive region 111 is hydrophilic, the region of the transparent matrix 112 around the primitive region 111 is hydrophobic, and the pigment ink 41 can be uniformly and evenly distributed on the surface of the primitive region 111. Due to the separation of the transparent matrix 112, the pigment ink 41 between the different pixel regions 111 does not overflow 1 to cause a blending problem of the pigment. In the present embodiment, the pigment ink 41 is a photocurable ink containing a pigment for providing color characteristics, a resin binder, a polyfunctional monomer having a vinyl unsaturated double bond, and a photopolymerization initiator. , dispersants and other additives. The red pigment for providing color characteristics to the ink may be a naphthol red pigment, a disazo condensate pigment, etc., the blue pigment includes a copper phthalocyanine pigment, and the green pigment includes a copper phthalocyanine pigment and a metal complex thereof. .

Referring to FIG. 3c, in the embodiment, step S303 is specifically: exposing the transparent substrate 11 to which the pigment ink 41 has been applied to the ultraviolet light source 51. Since the transparent substrate 11 is made of a polycarbonate (PC) material, the melting temperature of the polycarbonate is Between 260 and 340 ° C, there is a characteristic of not being resistant to high temperatures. Therefore, in the present embodiment, the curing of the pigment ink 41 is performed by ultraviolet curing (UV curing). The transparent substrate 11 to which the pigment ink 41 has been applied is exposed to the ultraviolet light source 51, and generally has a UV curing energy of less than 1000 mj/cm2, and in the present embodiment, the UV curing energy is less than 500 mj/cm2.

After the pigment ink 41 is UV-cured, a color filter film is formed on the transparent substrate 11. Generally, the coating amount of the pigment ink 41 is controlled in step S302 so that the thickness of the formed color filter film is between 0.1 and 10 μm. In the present embodiment, the color filter film has a color filter film of three colors of R, G, and B having a thickness of about 5 μm.

The pigment ink 41 may also be selected from a thermosetting ink having low-temperature curing properties, and the main components of the ink include a pigment for providing color characteristics, a resin binder, a polyfunctional monomer having a vinyl unsaturated double bond, and a thermal polymerization initiator. , dispersants and other additives. A heat-curing ink using a low-temperature curing property can be thermally cured. Since the transparent substrate 11 is a flexible plastic having high light transmittance and does not have heat resistance, the curing temperature of the pigment ink is generally less than 100 ° C.

FIG. 5 is a sub-flowchart of step S301 in the second embodiment of the present invention. Fig. 6 is a schematic view showing a manufacturing process of a color filter having a flexible substrate in a second embodiment of the present invention.

In the second embodiment of the present invention, step S301 specifically includes the steps of:

In step S3013, a transparent photosensitive material 60 is coated on the transparent substrate 12.

Referring to FIG. 6a, as in the first embodiment, in the second embodiment, the transparent substrate 12 is also made of a flexible plastic having high light transmittance, and the flexible substrate is coated with a transparent photosensitive material 60, in the second. In the embodiment, the photosensitive material 60 is a photosensitive resin combination. The photosensitive resin composition contains a bismuth-soluble resin binder, a photopolymerization initiator, and other additives, and the additive includes a dispersant, a binder promoter, an antioxidant, an ultraviolet absorber, and a thermal polymerization inhibitor.

In step S3014, the transparent substrate 12 is exposed to light by the hood 22.

Referring to FIG. 6b, the hood 22 is placed on the transparent substrate 12. The surface of the transparent substrate 12 that is not shielded by the hood 22 is photopolymerized by light, and the surface area of the surface region is reduced and the hydrophobicity is enhanced. After the transparent substrate 12 is exposed, the surface of the transparent substrate 12 that is not shielded by the hood 22 forms a transparent matrix 122 that divides the transparent substrate 12 into a plurality of primitive regions 121. The transparent matrix 122 has different surface wettability with the primitive region 121, the transparent matrix 122 exhibits hydrophobicity, and the primitive region 121 exhibits hydrophilicity. In the second embodiment, the wetting angle of the transparent matrix 122 and the primitive region 121 is selected to be different by 30 or more.

Referring to FIG. 6c and FIG. 6d, in the second embodiment, steps 302 and 301 are the same as in the first embodiment, and the pigment ink 42 is positioned and applied in the primitive region 121 by using the nozzle 32. The transparent substrate 12 to which the pigment ink 42 has been applied is then exposed to the ultraviolet light source 52. In the second embodiment, the UV curing energy is less than 150 mj/cm2. After the pigment ink 42 is UV-cured, a filter film of three colors of R, G, and B having a film thickness of about 2 μm is formed.

In other embodiments of the present invention, step 301 may further comprise forming a low surface energy, hydrophobic transparent matrix on the transparent substrate by sandblasting, etching, or the like.

Fig. 7 is a schematic view showing the structure of a reflective electronic paper having a flexible filter. The electronic paper 70 includes a substrate 71, an electronic paper body 72, and a filter 73, and the filter 73 has a flexible lining The bottom color filter film, the electronic paper body 72 includes a first electrode 721, an electrophoretic layer 723, and a second electrode 722. The filter 73 having a flexible substrate is bonded to the electronic paper main body 72, and the electronic paper 70 can be displayed in full color by the filter 73.

It is to be understood by those skilled in the art that the above embodiments are only intended to illustrate the invention, and are not intended to limit the invention, as long as it is within the spirit of the invention Changes and modifications are intended to fall within the scope of the invention.

11‧‧‧Transparent substrate

111‧‧‧Element area

112‧‧‧Transparent Matrix

21‧‧‧ hood

31‧‧‧Nozzles

41‧‧‧Pigment ink

411‧‧‧Red pigment ink

412‧‧‧Green pigment ink

413‧‧‧Blue pigment ink

51‧‧‧UV light source

Claims (8)

A method of manufacturing a color filter, the method comprising the steps of: placing a flexible transparent substrate in a carbon tetrafluoride atmosphere; and performing plasma processing on the transparent substrate without the surface of the hood shielding region by using a hood The surface of the transparent substrate after the plasma treatment forms a transparent matrix having a surface wettability different from the surface of the transparent substrate covered by the hood shielding region, the transparent matrix dividing a plurality of primitive regions on the transparent substrate, the transparent matrix and The element regions have different surface wettability; the pigment ink is coated in a plurality of primitive regions by inkjet printing; and the pigment ink is cured to form a plurality of color filter films. The method of manufacturing a color filter according to claim 1, wherein the transparent matrix and the wetttage angle of the primitive region are different by 10° or more. The method of manufacturing a color filter according to claim 4, wherein the transparent matrix and the wetttage angle of the primitive region are different by 50° or more. The method for producing a color filter according to claim 1, wherein the transparent substrate is polyisoprene, polycarbonate, polyethylene terephthalate, polymethyl methacrylate One of the esters. The method for producing a color filter according to claim 1, wherein the method of curing the pigment ink is a thermal curing method or an ultraviolet curing method. The method for producing a color filter according to claim 5, wherein the pigment ink is thermally cured, and the heat curing temperature is less than 100 °C. The method for manufacturing a color filter according to claim 5, wherein The ink is UV-cured, and the UV curing energy is less than 500mj/cm2. The method of manufacturing a color filter according to claim 1, wherein the color filter film formed by curing the pigment ink has a thickness of 0.1 to 10 μm.