TW201736876A - Flexible color filter and method of preparing the same - Google Patents

Abstract

The present invention relates to a flexible color filter prepared by carrying out procedures on a carrier substrate and the preparation method thereof in which a protective layer is formed before a black matrix layer is formed and the black matrix layer and a colorant layer are formed successively thereon.

Description

Flexible color filter and preparation method thereof

The present invention relates to a flexible color filter and a method of preparing the same. In particular, the present invention relates to a flexible color filter prepared by performing a procedure on a carrier substrate and a method of preparing the same.

As the Internet becomes more prevalent and the amount of information to be delivered increases explosively, there will be an "ubiquitous display" environment where information can be accessed anytime, anywhere. Therefore, portable displays, such as notebook computers, electronic organizers, and PDAs, play an important role. In order to realize this ubiquitous display environment, the display is portable, so that information can be directly accessed at a desired time and place, and a large screen feature for displaying various multimedia information is also required. Therefore, in order to simultaneously satisfy this portability and large screen characteristics, it is required to develop a display that can be folded, which is deployed as a display and folded and stored while being carried. Representative examples of flat panel display devices include a liquid crystal display (LCD) and an organic light emitting diode (OLED) display. Compared with conventional LCDs, OLEDs have advantages such as a very light and thin screen, a wide color reproduction range, a fast response time, and a high contrast ratio. In addition, OLED is booming and is most suitable for displays for flexible displays. In particular, white OLED displays using white light sources are being widely studied by researchers at home and abroad for their high efficiency, high resolution and long life characteristics, and are being realized for various applications of large-area high-quality displays and general illumination. Color filters are used in full color implementations in white OLED displays. The color filter contains red, green, and blue colored regions and combines light traveling therethrough to express color. Typically, a black matrix pattern is formed to block light (except for the pixel regions) and to prevent color mixing at the boundaries of the respective colorant layers, and a colorant layer is formed thereon by patterning. At this time, if the adhesion of the black matrix pattern is insufficient, the black matrix pattern may be damaged when the patterning is repeated to form the toner region, thereby causing a light leakage phenomenon or poor color reproducibility. In addition, this problem hinders the implementation of a fine pattern of one of the color filters. A technique for improving the adhesion of a film using a buffer layer is disclosed in Korean Patent Registration No. 10-0325119. The disclosed method comprises: forming a buffer layer on the overcoat layer to improve an overcoat layer for protecting a colorant layer in a color filter substrate of a liquid crystal display device and maintaining surface smoothness and for applying a voltage to drive Adhesion of the transparent conductive film layer of the liquid crystal; and forming a transparent conductive film layer thereon.

[Technical Problem] An object of the present invention is to provide a flexible color filter which has enhanced color reproducibility by improving adhesion between a black matrix layer of a color filter and a lower layer or a base substrate thereof, And a method of preparing the flexible color filter. Another object of the present invention is to provide a flexible color filter having a high-resolution fine pattern by improving adhesion between a black matrix layer of a color filter and a lower layer or a base substrate thereof, and A method of making the flexible color filter. [Technical Solution] According to an aspect of the present invention, a flexible color filter comprising: a separation layer; a protective layer formed on the separation layer; and a black matrix (BM) layer, It is formed on the protective layer; and a colorant layer is formed in the middle of the BM layer, wherein the separation load of the BM layer and the lower layer thereof is 2.5 N/mm ² or more. The protective layer may be formed to cover one side surface of the separation layer. The flexible color filter may further include a base film disposed under the separation layer, and may further include an outer coating layer formed on the black matrix layer and the colorant layer. The protective layer may include at least one of an organic insulating film and an inorganic insulating film. In accordance with another aspect of the present invention, a flexible display device is provided that includes one of the flexible color filters described above. According to still another aspect of the present invention, a method for preparing a flexible color filter comprising the steps of: applying a composition for forming a separation layer to a carrier substrate is provided Forming a separation layer; forming a protective layer on the separation layer; forming a black matrix (BM) layer on the protective layer and forming a colorant layer in the middle of the BM layer; and removing the carrier substrate, wherein the BM The separation load of the layer from its lower layer is 2.5 N/mm ² or more. The protective layer can be formed by applying or depositing a composition for forming one of the protective layers. The method for preparing a flexible color filter according to the present invention may further comprise the step of forming an overcoat layer on the BM layer and the colorant layer. Further, the method for preparing a flexible color filter according to the present invention may further comprise the step of attaching a base film to a surface from which one of the carrier substrates is removed after the removing of the carrier substrate . [Advantageous Effect] According to the flexible color filter of the present invention, the adhesion between a BM layer and its underlying layer or a base substrate is enhanced by forming a protective layer before forming the BM layer. As the adhesion of the BM layer is enhanced, damage to the BM layer is reduced in subsequent processing, which achieves a fine pattern of the BM layer and the toner layer and prevents light leakage. Therefore, a flexible color filter having high resolution and excellent color reproducibility and a flexible display device including the flexible color filter can be obtained.

Hereinafter, preferred embodiments of a flexible color filter and a method of fabricating the same according to the present invention will be described in detail with reference to the accompanying drawings. However, the drawings that are attached to the present invention are only examples for describing the present invention, and the present invention is not limited by the drawings. Furthermore, for a clearer expression, some elements may be enlarged, reduced or omitted in the drawings. The present invention proposes a flexible color filter having an enhanced adhesion of a BM layer by forming a protective layer under the BM layer of a color filter prepared by performing a process on a carrier substrate. . 1 is a cross-sectional view of one of the flexible color filters in accordance with an embodiment of the present invention. Referring to FIG. 1, a flexible color filter according to an embodiment of the present invention includes a separation layer 120, a protective layer 130, a black matrix (BM) layer 140 patterned on the protective layer 130, and is formed on One of the colorant layers 150 in the pixel region intermediate the BM layer 140. The separation layer 120 is formed to strip one layer from a carrier substrate after completion of the color filter in the preparation method of the present invention. Therefore, the separation layer 120 can be separated from the carrier substrate by a physical force and laminated on a base film after separation. The separation layer 120 preferably has a peel strength of 1 N/25 mm or less, more preferably 0.1 N/25 mm or less when it is separated from the carrier substrate. That is, the separation layer 120 is preferably formed of a material that can maintain one of the physical forces applied during separation of the separation layer 120 from the carrier substrate within 1 N/25 mm, particularly within 0.1 N/25 mm. If the peeling strength of the separation layer 120 exceeds 1 N/25 mm, it is difficult to cleanly separate the separation layer from the carrier substrate, and thus the separation layer 120 may remain on the carrier substrate. Further, cracks may be generated on one or more of the separation layer 120, the protective layer 130, the BM layer 140, the colorant layer 150, and the overcoat layer 160. Specifically, the peeling strength of the separation layer 120 is preferably 0.1 N/25 mm or less because it allows control of the curling in the film after separation from the carrier substrate. The separation layer 120 may be made of, for example, a polymer material selected from at least one of the group consisting of polyacrylate, polymethacrylate (eg, PMMA), polyimine, polyamine, Polyvinyl alcohol, polylysine, polyolefin (for example, PE, PP), polystyrene, polynorbornene, phenyl maleimide copolymer, polyazobenzene, polyphenylene phenylene Formamide, polyester (eg PET, PBT), polyarylate, cinnamate polymer, coumarin polymer, benzalkonium polymer, chalcone polymer and aromatic acetylene polymer. The separation layer 120 preferably has a thickness of one of 10 nm to 1000 nm, more preferably 50 nm to 500 nm. If the thickness of the separation layer 120 is less than 10 nm, the separation layer may be unevenly formed to induce formation of a non-uniform upper pattern, and the peel strength of the separation layer may locally rise to cause fracture, or the hemming control may be in the separation layer and the carrier. The substrate fails after separation. If the thickness of the separation layer is more than 1000 nm, the peel strength of the separation layer may not be further lowered, and the flexibility of the film may be deteriorated. The separation layer 120 preferably has a surface energy of from 30 mN/m to 70 mN/m after it is peeled off from the carrier substrate. Furthermore, the surface energy difference between the separation layer 120 and the carrier substrate is preferably 10 mN/m or more. The separation layer 120 should maintain a stable adhesion to the carrier substrate until it is separated from the carrier substrate, and then should be easily separated without the breakage or curling of the color filter. When the surface of the separation layer 120 can conform to the range of 30 mN/m to 70 mN/m, the peel strength can be controlled to ensure good adhesion between the separation layer 120 and the adjacent protective layer 130 to improve the efficiency of the process. . Further, when the surface energy difference between the separation layer 120 and the carrier substrate is 10 mN/m or more, it can be easily separated from the carrier substrate to prevent breakage or crack generation of the color filter. The protective layer 130 is formed on the separation layer 120 and serves as a reinforced adhesive layer of the BM layer formed on the protective layer 130. The protective layer 130 may be formed of an organic insulating film or an inorganic insulating film. When the protective layer 130 is formed of an organic layer to ensure the function of a flexible color filter, the polymeric material described above with respect to the separation layer 120 can be used. The protective layer 130 may have a thickness of one of 0.5 μm to 5 μm. The BM layer 140 is used to shield light in regions other than the pixel regions and to prevent color mixing on one of the borders of the respective colorant layers. Thus, BM layer 140 is formed of an opaque material and patterned to surround the pixel regions. A BM layer 140 is formed on the protective layer 130 to enhance adhesion to the underlying layer. According to an embodiment of the present invention, the separation load of the BM layer 140 formed on the protective layer 130 is an average of 2.5 N/mm ² or more. Adhesive layer 150 is used to implement full color display, and typically red, green, and blue colors are patterned and disposed intermediate BM layer 140. However, the colorant layer does not necessarily contain all of the red, green, and blue patterns, and does not necessarily include only red, green, and blue patterns. The fact is that only some of these colors can be included according to the color model, or an additional color pattern such as white can be included. Meanwhile, when external light reaches the coloring agent layer of each color, only light having a respective wavelength is transmitted and light having two outer two wavelengths is absorbed. Therefore, the amount of incident light of external light can be effectively reduced, which allows the colorant layer to function as a polarizing plate to prevent reflection of external light. The BM layer 140 and the color former layer 150 can also be formed from the polymeric materials described above. Although not shown in the drawings, the color filter according to an embodiment of the present invention shown in FIG. 1 may constitute one of a flexible base film attached to the lower side of the separation layer 120. Color filter. The base film may be a transparent film or a polarizing plate. The transparent film is not limited if it has good transparency, mechanical strength and thermal stability. Specific examples of the transparent film may include: a thermoplastic resin such as a polyester resin such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, and polybutylene terephthalate a diester; a cellulose resin such as diethyl cellulose and triethyl fluorenyl cellulose; a polycarbonate resin; an acrylate resin such as poly(methyl) methacrylate and poly(ethyl) acrylate; Styrene resin, such as polystyrene and acrylonitrile-styrene copolymer; polyolefin resin such as polyethylene, polypropylene, polyolefin having a cyclic or norbornene structure, and ethylene-propylene copolymer; vinyl chloride resin Amidoxime resin, such as nylon and aromatic polyamine; quinone imine resin; polyether oxime resin; oxime resin; polydiether ketone resin; polyphenylene sulfide resin; vinyl alcohol resin; vinylidene chloride resin; Alkyd resin; allyl resin; polyacetal resin and epoxy resin. Further, a film composed of a blend of one of thermoplastic resins may be used. In addition, heat curable or UV curable resins such as (meth) acrylates, urethanes, urethane acrylates, epoxies, and enamel resins may be used. This transparent film can have a suitable thickness. For example, the thickness of the transparent film may range from 1 μm to 500 μm, preferably from 1 μm to 300 μm, more preferably from 5 μm to 200 μm, in view of strength and handling workability or thin layer properties. The transparent film may contain at least one suitable additive. Examples of the additive may include a UV absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a color preventive agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment or A coloring agent. The transparent film may include various functional layers including a hard coat layer, an anti-reflection layer, and a gas barrier layer, but the invention is not limited thereto. That is, other functional layers may also be included depending on the intended use. The transparent film can be surface treated if desired. For example, the surface treatment can be carried out by a drying method such as plasma, corona and undercoat treatment or by a chemical method such as alkali treatment (including saponification reaction). Furthermore, the transparent film may be an isotropic film, a retardation film or a protective film. In the case of an isotropic film, it is preferred to satisfy an in-plane retardation (Ro) of 40 nm or less, preferably 15 nm or less, and -90 nm to +75 nm, preferably -80 nm to + One of 60 nm, especially -70 nm to +45 nm thickness retardation (Rth), in-plane retardation (Ro) and thickness retardation (Rth) is represented by the following equation. Ro=[(nx-ny)×d] Rth=[(nx+ny)/2-nz]×d where nx and ny are each one of the principal refractive indices on a film plane, and the thickness direction of the nz film is One of the refractive indices, and one of the thicknesses of the d-type film. The retardation film can be prepared by uniaxially stretching or biaxially stretching a polymer film (a polymer coating or a liquid crystal coating), and is generally used to improve or control the optical properties of a display, for example, Viewing angle compensation, color sensitivity improvement, light leakage prevention, or color control. The retardation film may comprise a half wave (1/2) or a quarter wave (1/4) plate, a positive C plate, a negative C plate, a positive A plate, a negative A plate, and a double plate. The protective film may be a polymer resin film including one of pressure-sensitive adhesive (PSA) layers on at least one surface thereof, or a self-adhesive film such as polypropylene. The protective film can be used to protect the surface of the color filter and improve workability. The polarizing plate may be any polarizing plate known for use in a display panel. Specifically, polyvinyl alcohol (PVA), cellulose triacetate (TAC) or cyclic olefin polymer (COP) membranes can be used, but not limited to. In accordance with another embodiment of the present invention, an overcoat layer can be formed over the BM layer 140 and the colorant layer 150 to protect the pattern during adhesion of the color filter to the base film. 2 is a cross-sectional view of one of the flexible color filters including an overcoat layer in accordance with another embodiment of the present invention. As shown in FIG. 2, a flexible color filter according to another embodiment of the present invention includes a separation layer 120, a protective layer 130, a BM layer 140 patterned on the protective layer 130, and a colorant. Layer 150, and an outer coating 160 covering one of BM layer 140 and colorant layer 150. Overcoat layer 160 can also be formed from the polymeric materials described above. Now, a method of preparing one of the flexible color filters having the structure described above according to an embodiment of the present invention will be described in detail. 3a through 3g are cross-sectional views schematically showing the procedure of an embodiment of a method of preparing a flexible color filter according to the present invention. First, as shown in FIG. 3a, a carrier substrate 170 is prepared, which is applied to form a composition of a separation layer, and a separation layer 120 is formed. The carrier substrate 170 is preferably a glass substrate, but is not limited thereto. That is, other kinds of materials (if they are heat resistant materials) can be used, which can withstand one of the treatment temperatures of the electrode formation and maintain flattening without deformation at a high temperature. The composition used to form a separate layer can be applied by a conventional coating method known in the art. For example, spin coating, die coating, spray coating, roll coating, screen coating, slit coating, dip coating, gravure coating, and the like can be mentioned. Alternatively, an ink jet method can be used. After coating, the composition for forming a separation layer is subjected to curing by heat curing or UV curing to form the separation layer 120. Thermal curing and UV curing can be carried out separately or in combination. For heat curing, an oven or hot plate can be used. The heating temperature and time depend on the composition, and for example, curing can be carried out at 80 ° C to 250 ° C for 10 minutes to 120 minutes. Next, as shown in FIG. 3b, a protective layer 130 is formed on the separation layer 120. The protective layer 130 may be formed by applying an organic insulating film or by depositing an inorganic insulating film. When an organic insulating film is used, a well-known coating method can be used as a coating method. For example, spin coating, die coating, spray coating, roll coating, screen coating, slit coating, dip coating, gravure coating, and the like can be mentioned. Alternatively, an ink jet method can be used. Meanwhile, since the separation layer 120 can be peeled off by a physical force and the peel strength is extremely weak (as described above), the protective layer 130 is preferably formed to cover both sides of the separation layer 120. Next, as shown in FIG. 3c, a BM layer 140 is formed on the protective layer 130. The BM layer 140 can be formed by patterning an opaque organic material. Now, as shown in FIG. 3d, one of the red (R), green (G), and blue (B) colors of the colorant layer 150 is formed in the middle of the pattern of the BM layer 140. The color of the colorant layer 150 can be arbitrarily selected, and the order in which the colors are formed can also be arbitrarily selected. In accordance with an embodiment of the present invention, BM layer 140 and colorant layer 150 may be implemented to have a fine pattern, and damage of BM layer 140 during formation of colorant layer 150 is minimized due to enhanced adhesion of BM layer 140. . Next, as shown in FIG. 3e, an overcoat layer 160 for a protective pattern is formed on the BM layer 140 and the colorant layer 150. Subsequently, as shown in FIG. 3f, the carrier substrate 170 is separated from the separation layer 120. The separation of the carrier substrate 170 from the separation layer 120 can be performed at room temperature and can be performed by a physical peeling, wherein the carrier substrate 170 made of, for example, glass is stripped from the separation layer 120. Examples of the stripping method may include, but are not limited to, detachment and stripping. Thereafter, as shown in FIG. 3g, a base film 110 is attached to the surface of one of the separation layers 120 from which the carrier substrate 170 is removed. Although not shown in the drawings, the base film 110 may be adhered to the separation layer 120 using an adhesive layer (and a photocurable adhesive may be used). Because the photocurable adhesive does not require a separate drying process after photocuring, the process is simple. Therefore, the productivity is increased. In the present invention, a photocurable adhesive usable in the art can be used without particular limitation. For example, a composition including an epoxy compound or an acrylic monomer can be used. To cure the adhesive layer, light can be used, such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays; electromagnetic waves such as X-rays, gamma rays, and electron beams, proton beams, and neutron beams can also be used. However, UV curing is advantageous in terms of curing speed, curing device availability, cost, and the like. A high pressure mercury lamp, an electrodeless lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light, and the like can be used as one of the UV curing sources. In the following, an example of a effect of the present invention which is carried out to find the adhesion of the protective layer-enhanced BM layer and a comparative example are described. However, this is to assist the understanding of the invention and is not intended to limit the invention. Examples and Comparative Examples Example Preparation of 5 x 5 cm (thickness: 0.7 mm) one of a glass substrate, the cleaning with ethanol and deionized water and dried by blowing. Next, a composition for forming a protective layer was applied by spin-coating with 0.50 ml of a drop using a micropipette and spinning at 450 rpm for 10 seconds. It was placed in a horizontal position for about 3 minutes, pre-cured at 100 degrees for 90 seconds, exposed and cured at 230 degrees for 20 minutes to form a protective layer of 1.15 μm. Thereafter, a black matrix layer is formed on top of the protective layer. Subsequently, it is aged at room temperature for more than 4 hours, and one of the seals having a diameter of 3 mm to 4 mm has been kept frozen at -20 degrees, an upper glass substrate is attached, and is applied by gravity. A pressure of up to 1 minute to assemble with an upper glass substrate. Next, it was exposed to 7000 mJ of energy and 18 mW of illumination and cured at 200 degrees for 1 hour to complete one of the test pieces of the example. The structure of the test piece thus obtained is shown in Figures 4a and 4b. 4a and 4b are a cross-sectional view and a plan view, respectively, of the completed test piece. As shown in FIG. 4a, the test piece has a structure in which a glass substrate 710, a protective layer 720, a BM layer 730, a sealant 740, and an upper glass substrate 750 are stacked in a stack, and as shown in FIG. As shown in 4b, the upper glass substrate 750 and the lower glass substrate 710 are configured to cross each other. Comparative Example A comparative example has the same structure as the test piece of the example by the same process, and the only BM layer is formed on a glass substrate except for a protective layer, and a cross-sectional view thereof is shown in FIG. As shown in FIG. 5, the protective layer is not present in the comparative example, and only the glass substrate 810, a BM layer 830, a sealant 840, and an upper glass substrate 850 are stacked in a stack. Next, a UTM tester INSTRON 5567 was used to measure the adhesion of the black matrix. Specifically, the maximum load per sealant area is calculated by pulling up the glass substrate at a rate of 10 mm/min and pulling down the glass substrate until the lower glass substrate is separated from the black matrix. Table 1 below shows the measurement results. [Table 1] As shown in Table 1, the average load of the example of the present invention was 2.61 N/mm ² , which was able to withstand an additional load of 0.52 N/mm ² compared to the comparative example without the protective layer. The variation range between the maximum load and the minimum load of the example of the present invention is 0.77 and the standard deviation is 0.22, which is about one-half of the variation range and standard deviation of the comparative example. This shows an extremely stable adhesive performance. While the invention has been shown and described with respect to the specific embodiments and embodiments of the present invention, it is understood that Various changes and modifications are made in the spirit and scope of the invention. Accordingly, the scope of the invention is defined by the scope of the appended claims and their equivalents.

110‧‧‧ basement membrane
120‧‧‧Separation layer
130‧‧‧Protective layer
140‧‧‧Black matrix (BM) layer
150‧‧‧Colorant layer
160‧‧‧Overcoat
170‧‧‧ Carrier substrate
710‧‧‧Lower glass substrate
720‧‧‧protection layer
730‧‧‧Black matrix (BM) layer
740‧‧‧Sealant
750‧‧‧Upper glass substrate
810‧‧‧Lower glass substrate
830‧‧‧Black matrix (BM) layer
840‧‧‧Sealant
850‧‧‧Upper glass substrate

1 is a cross-sectional view of one of the flexible color filters in accordance with an embodiment of the present invention. 2 is a cross-sectional view of one of the flexible color filters in accordance with another embodiment of the present invention. 3a through 3g are cross-sectional views schematically showing the procedure of an embodiment of a method of preparing a flexible color filter according to the present invention. 4a and 4b are respectively a cross-sectional view and a plan view of a test piece according to an example of the present invention. Figure 5 is a cross-sectional view of one of the test pieces of a comparative example.

120‧‧‧Separation layer

130‧‧‧Protective layer

140‧‧‧Black matrix (BM) layer

150‧‧‧Colorant layer

Claims (10)

A flexible color filter comprising: a separation layer; a protective layer formed on the separation layer; a black matrix layer formed on the protective layer; and a colorant layer formed on In the middle of the black matrix layer, the separation load of the black matrix layer and the lower layer thereof is 2.5 N/mm ² or more. The flexible color filter of claim 1, wherein the protective layer is formed to cover a side surface of the separation layer. The flexible color filter of claim 1, further comprising a base film disposed under the separation layer. The flexible color filter of claim 1, further comprising an overcoat layer formed on the black matrix layer and the colorant layer. The flexible color filter of any one of claims 1 to 4, wherein the protective layer comprises at least one of an organic insulating film and an inorganic insulating film. A flexible display device comprising the flexible color filter of any one of claims 1 to 4. A method for preparing a flexible color filter, comprising the steps of: forming the separation layer by applying a composition for forming a separation layer onto a carrier substrate; Forming a protective layer thereon; forming a black matrix layer on the protective layer and forming a colorant layer in the middle of the black matrix layer; and removing the carrier substrate, wherein the separation load of the black matrix layer and the lower layer thereof is 2.5 N/ Mm ² or larger. A method for preparing a flexible color filter according to claim 7, wherein the protective layer is formed by applying or depositing a composition for forming one of the protective layers. A method for preparing a flexible color filter according to claim 7, further comprising the step of forming an overcoat layer on the black matrix layer and the colorant layer. A method for preparing a flexible color filter according to claim 7, further comprising the step of attaching a base film to a surface from which one of the carrier substrates is removed after the removing of the carrier substrate .