KR102315129B1 - Flexible Color Filter, Flexible Display Device Including the Same, and Fabrication Method Thereof - Google Patents

Abstract

Disclosed are a flexible color filter including a protective layer, a black matrix layer formed on the protective layer and partitioning a pixel area, a buffer layer formed in the pixel area, and a colored layer formed on the buffer layer, and a flexible display device including the same. According to the present invention, in the flexible color filter, the adhesion between the protective layer and the colored layer can be improved by forming a buffer layer of the same material as that of the black matrix layer in the pixel area.

Description

Flexible color filter, flexible display device including same, and manufacturing method thereof

The present invention relates to a flexible color filter, a flexible display device including the same, and a manufacturing method thereof.

Flexible display means a display that can be bent, bent, or rolled without loss of characteristics, and technology development is being made in the form of flexible LCD, flexible OLED, and electronic paper.

In order to realize a flexible display, various plastic substrates are being developed as flexible substrates to replace the existing glass substrates, and the substrates of various components constituting the flexible display are being replaced by these plastic substrates in the glass substrate. As a specific example, a color filter substrate including a film substrate made of polyimide and a color filter unit formed on the film substrate disclosed in Korean Patent Registration No. 10-1174148, or a flexible substrate disclosed in Korean Patent Application Laid-Open No. 10-2013-0047971 floor; a buffer layer applied to the entire upper surface of the flexible layer; a display element formed on the upper surface of the buffer layer; and a flexible organic light emitting diode display including a back panel attached to the rear surface of the flexible layer and having elasticity and flexibility to support the display element.

On the other hand, an organic light emitting diode (OLED) panel may reflect external light such as sunlight and lighting due to electrode exposure, and visibility and contrast ratio may be deteriorated due to the reflected external light, and thus display quality may deteriorate.

Accordingly, as disclosed in Korean Patent Laid-Open No. 2009-0122138, in order to block the reflection of external light on the surface in the power-off state and to have a black feeling, a circular polarizing plate combining a linear polarizer and a λ/4 retardation layer is used as an anti-reflection polarizing plate It can be used by attaching it to the viewer side of the OLED panel.

However, when such an anti-reflection polarizing plate is applied, a problem of lowering the luminance of the OLED panel occurs. Accordingly, interest in flexible color filters as a product that can replace the anti-reflection polarizing plate is increasing.

However, in the flexible color filter, the adhesion between the colored layer and its lower layer is not sufficient, and thus the colored layer may be peeled off, and there may be problems such as light leakage or poor color reproducibility due to the colored layer peeling off. In addition, this problem becomes an obstacle to realizing a fine pattern of the color filter.

Republic of Korea Patent No. 10-1174148 Republic of Korea Patent Publication No. 10-2013-0047971 Korean Patent Publication No. 2009-0122138

The present invention is to solve the problems of the prior art, a flexible color filter capable of preventing light leakage and improving color reproducibility by improving adhesion between a colored layer of a color filter and a lower layer thereof, and a flexible display including the same An object thereof is to provide an apparatus and a method for manufacturing the same.

Another object of the present invention is to improve the adhesion between the colored layer of the color filter and the lower layer thereof, thereby realizing the fine pattern of the color filter to achieve high resolution, a flexible color filter including the same, and a method for manufacturing the same is to provide

In order to solve the above problems, an aspect of the present invention provides a protective layer, a black matrix (BM) layer formed on the protective layer and partitioning a pixel area, a buffer layer formed in the pixel area, and a buffer layer formed on the buffer layer It provides a flexible color filter comprising a colored layer.

Here, the ratio of the area of the buffer layer to the area of the pixel region may be 1 to 40%, more preferably 5 to 15%.

The BM layer and the buffer layer may be formed of the same material.

The BM layer may include carbon black.

At least one of the protective layer, the BM layer and the colored layer may be formed of a low-reflection material.

According to another aspect of the present invention, there is provided a flexible display device including the flexible color filter as described above and a display panel coupled to the flexible color filter.

Here, the display panel may include a base film, a thin film transistor on the base film, an organic light-emitting diode (OLED) on the thin film transistor, and an encapsulation layer on the OLED.

The display panel may further include a touch sensor layer on the encapsulation layer.

According to another aspect of the present invention, forming a separation layer on a first carrier substrate, forming a passivation layer on the separation layer, a black matrix (BM) for partitioning a pixel area on the passivation layer A method of manufacturing a flexible color filter is provided, comprising the steps of: forming a layer and a buffer layer in a pixel area; and forming a colored layer on the buffer layer.

Here, the ratio of the area of the buffer layer to the area of the pixel region may be 1 to 40%, more preferably 5 to 15%.

In addition, the BM layer and the buffer layer may be formed of the same material, and the BM layer may include carbon black.

Here, at least one of the protective layer, the BM layer, and the colored layer may be formed of a low-reflection material.

According to another aspect of the present invention, the steps of manufacturing a flexible color filter by the above-described method, combining the flexible color filter with a display panel formed on a second carrier substrate, and a first carrier substrate and a separation layer and a second A method of manufacturing a flexible display device comprising removing a carrier substrate is provided.

In the flexible color filter according to the present invention, the adhesion between the protective layer and the colored layer can be improved by forming a buffer layer of the same material as the black matrix layer in the pixel region. As such, when the adhesion between the protective layer and the colored layer is improved, light leakage due to peeling of the colored layer can be prevented and color reproducibility of the color filter can be improved.

In addition, in the flexible color filter according to the present invention, it is possible to implement a fine pattern of the color filter by improving the adhesion between the protective layer and the colored layer through the buffer layer.

1 is a cross-sectional view of a flexible color filter according to an embodiment of the present invention.
2 is a cross-sectional view of a flexible display device according to an embodiment of the present invention.
3A to 3G are cross-sectional views of each step of the manufacturing method of a flexible display device according to an embodiment of the present invention.

Hereinafter, preferred embodiments of a flexible color filter, a flexible display including the same, and a manufacturing method thereof according to the present invention will be described in detail with reference to the drawings. However, the drawings attached to the present specification are only examples for explaining the present invention, and the present invention is not limited by the drawings. In addition, for convenience of description, some components may be exaggerated, reduced, or omitted in the drawings.

1 is a cross-sectional view of a flexible color filter according to an embodiment of the present invention.

Referring to FIG. 1 , a flexible color filter according to an embodiment of the present invention includes a protective layer 130 , a black matrix (BM) layer 140 and a buffer layer 150 formed on the protective layer 130 , and A colored layer 160 may be included.

The protective layer 130 may be formed of an organic insulating layer or an inorganic insulating layer.

When the protective layer 130 is formed of an organic insulating layer, a polymer material may be used. The polymer material is, for example, polyacrylate, polymethacrylate (eg PMMA), polyimide, polyamide, polyvinyl alcohol, polyamic acid ( polyamic acid), polyolefin (eg, PE, PP), polystyrene, polynorbornene, phenylmaleimide copolymer, polyazobenzene, polyphenylenephthalamide (polyphenylenephthalamide), polyester (eg, PET, PBT), polyarylate, cinnamate-based polymer, coumarin-based polymer, phthalimidine-based polymer, chalcone It contains at least one material selected from the group consisting of (chalcone)-based polymers and aromatic acetylene-based polymers.

The protective layer 130 may have a thickness of 0.5 to 5 μm.

The BM layer 140 is a light blocking layer that partitions a pixel area, blocks light except for the pixel area, and prevents color mixing at the boundary between each colored layer. Accordingly, the BM layer 140 is formed of an opaque material and is patterned to surround the pixel area.

The BM layer 140 is formed of a material including carbon black, and may include the above-described polymer material.

The buffer layer 150 is formed between the patterns of the BM layer 140 , that is, in the pixel area. The buffer layer 150 is formed of the same material as the BM layer 140 . The buffer layer 150 is formed together with the BM layer 140 in the same step as the BM layer 140 in the manufacturing process.

The buffer layer 150 is formed to cover 1 to 40% of the area of each pixel area. The buffer layer 150 serves to improve adhesion between the protective layer 130 and the colored layer 160 formed thereon in the pixel region. If the area occupied by the buffer layer 150 in the pixel region is too small (1% or less), it is difficult to exhibit the function of improving adhesion with the protective layer 130. The amount of light passing through the region is reduced, and when it exceeds 40%, it is difficult to secure sufficient transmittance. The area occupied by the buffer layer 150 in the pixel area is more preferably 5 to 15%.

The coloring layer 160 is a layer for realizing a color for a color display, and is typically patterned with red, green, and blue, and is disposed in a pixel area between the BM layers 140 . and formed on the buffer layer 150 . However, the colored layer 160 does not have to include all of the red, green, and blue patterns or only the red, green, and blue patterns. Only the pattern may be included, or a pattern of another color such as a white pattern may be further included.

The colored layer 160 may also be formed of the above-described polymer material, and at least one of the protective layer 130 , the BM layer 140 , and the colored layer 160 is preferably formed of a low-reflection material. In particular, it is preferable to use a material having a low reflectance as the material of the colored layer 160, and when the flexible color filter according to an embodiment of the present invention is used to prevent external light reflection in an OLED display, the transmittance for each color is the OLED light source. It is desirable to make it 50% or more at the center wavelength of .

As described above, by forming a buffer layer in the pixel region to improve the adhesion between the protective layer and the colored layer, it is possible to prevent light leakage and improve the color reproducibility of the color filter, and it is also possible to implement a fine pattern of the color filter.

Now, a flexible display device including a flexible color filter according to an embodiment of the present invention will be described.

2 is a cross-sectional view of a flexible display device according to an embodiment of the present invention.

As shown in FIG. 2 , the flexible display device according to an embodiment of the present invention includes a flexible color filter 100 , a flexible display panel 200 , and an adhesive layer for bonding the flexible color filter 100 and the display panel 200 ( 300) may be included.

The flexible color filter 100 includes a protective layer 130 and a color filter layer 170 , and may be the same as or similar to the flexible color filter according to the embodiment of the present invention described with reference to FIG. 1 . That is, the color filter layer 170 of FIG. 2 may include the BM layer 140 , the buffer layer 150 , and the coloring layer 160 as shown in FIG. 1 .

As shown in FIG. 2 , the display panel 200 includes a base film 220 , a thin film transistor (TFT) layer 230 , and an organic light-emitting diode (OLED) layer 240 . ), an encapsulation layer 250 , and a touch sensor layer 260 may have a structure in which they are sequentially stacked. The display panel 200 has components for the display panel formed on the flexible base film 220 , and has the same flexibility as the flexible color filter 100 , and thus a flexible display device can be configured. The flexible base film 220 will be described in more detail below with respect to the manufacturing method of the flexible display device of the present invention. However, the structure shown in FIG. 1 is provided as an example, and the structure is not particularly limited in the present invention as long as it can be used in a flexible display device.

An adhesive layer 300 for bonding the flexible color filter 100 and the display panel 200 is formed between the flexible color filter 100 and the display panel 200 . The adhesive layer 300 is made of an optically clear adhesive (OCA) or an optically clear resin (OCR).

Next, a method of manufacturing a flexible display device including a flexible color filter according to an embodiment of the present invention will be described.

3A to 3H are cross-sectional views of each step of the manufacturing method of a flexible display device according to an embodiment of the present invention.

First, as shown in FIG. 3A , after preparing the first carrier substrate 110 , a composition for forming a separation layer is applied to form the separation layer 120 .

It is preferable to use a glass substrate as the first carrier substrate 110 , but the present invention is not limited thereto and other materials may be used. However, a material having heat resistance that does not deform even at a high temperature to withstand the subsequent processing temperature, that is, can maintain flatness is preferable.

As a material of the separation layer 120 , a polymer material that is the same as or similar to that of the protective layer 130 described with reference to FIG. 1 may be used.

As a method of applying the composition for forming a separation layer, a known coating method may be used. For example, spin coating, die coating, spray coating, roll coating, screen coating, slit coating, dip coating, gravure coating, etc. are mentioned. Alternatively, an inkjet method may be used.

The composition for forming the separation layer is coated and cured to form the separation layer 120 . In this case, the curing process may be performed using either thermal curing or UV curing alone, or a combination of thermal curing and UV curing. When thermosetting is used, it may be heated by an oven, a hot plate, etc., and the heating temperature and time may vary depending on the composition, but for example, may be heat-treated at 80 to 250° C. for 10 to 120 minutes.

The separation layer 120 is a layer formed for separation from the first carrier substrate 110 after bonding of the flexible color filter 100 and the display panel 200 is completed in the manufacturing process of the flexible display device of the present invention, The peeling force of the surface facing the protective layer may be adjusted to facilitate peeling from the protective layer.

Next, as shown in FIG. 3B , the protective layer 130 is formed by applying a composition for forming a protective layer on the separation layer 120 .

The coating method and curing process of the composition for forming the protective layer are the same as described in the formation process of the separation layer 120 .

Now, as shown in FIG. 3C , the BM layer 140 and the buffer layer 150 are formed on the protective layer 130 .

The BM layer 140 may be formed by patterning to partition a portion forming a pixel using an opaque organic material including carbon black. When the BM layer 140 is patterned, it is not completely developed and a portion is protected. By allowing it to remain on the layer 130 , the buffer layer 150 may be simultaneously formed. That is, the BM layer 140 and the buffer layer 150 may be formed through the same process using the same material.

As described above with reference to FIG. 1 , the buffer layer 150 is formed to cover 1 to 40% of the area of each pixel area. The ratio of the area of the buffer layer to the area of the pixel region may be controlled by adjusting the temperature and time of the development process when the BM layer 140 is patterned. Specifically, the developing process temperature may be 20 to 25° C., and the time may be 40 to 80 seconds.

Next, as shown in FIG. 3D , a colored layer 160 is formed on the BM layer 140 and the buffer layer 150 .

The colored layer 160 is formed by applying each colored layer-forming composition for color expression to the pixel area partitioned by the BM layer 140 and exposing, developing, and thermally curing the composition in a predetermined pattern. Colors constituting the colored layer may be arbitrarily selected, and the order of formation for each color may also be arbitrarily selected.

At this time, due to the buffer layer 150 formed in the pixel region, the adhesion of the colored layer 160 to the protective layer 130 is improved, and thus, the colored layer peeling phenomenon due to overdevelopment can be prevented. Accordingly, color reproducibility of the display device is improved, and fine patterns can be formed.

Meanwhile, the portion including the BM layer 140 , the buffer layer 150 , and the colored layer 160 formed in this way may be referred to as a color filter layer 170 , and will be illustrated as one layer in the following drawings.

Now, in a process separate from that described with reference to FIGS. 3A to 3D , as shown in FIG. 3E , the display panel 200 is formed on the second carrier substrate 210 . The display panel 200 may be manufactured by any method known in the field of flexible display technology, and the manufacturing process thereof is not particularly limited in the present invention.

The second carrier substrate 210 is preferably a glass substrate like the first carrier substrate 110, but is not limited thereto, and other materials may be used. However, as in the case of the first carrier substrate 110 , a material having heat resistance that is not deformed even at high temperature to withstand the process temperature for subsequent TFT and OLED manufacturing, ie, has heat resistance capable of maintaining flatness, is preferable.

The base film 220 may be used without limitation as an optical film, but among them, it is preferable to use a film excellent in flexibility, transparency, thermal stability, moisture shielding properties, and the like.

Specific examples include polyester-based resins such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, and polybutylene terephthalate; Cellulose resins, such as a diacetyl cellulose and a triacetyl cellulose; polycarbonate-based resin; acrylic resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate; styrenic resins such as polystyrene and acrylonitrile-styrene copolymer; polyolefin-based resins such as polyethylene, polypropylene, polyolefin having a cyclo-based or norbornene structure, and an ethylene-propylene copolymer; vinyl chloride-based resin; amide resins such as nylon and aromatic polyamide; imide-based resin; polyether sulfone-based resin; sulfone-based resins; polyether ether ketone resin; sulfide polyphenylene-based resin; vinyl alcohol-based resin; vinylidene chloride-based resin; vinyl butyral-based resin; allylate-based resin; polyoxymethylene-based resins; and a film composed of a thermoplastic resin such as an epoxy-based resin, and a film composed of a blend of the above-mentioned thermoplastic resins can also be used. In addition, a film made of a thermosetting resin or ultraviolet curable resin such as (meth)acrylic, urethane, acrylic urethane, epoxy, or silicone may be used.

Meanwhile, for convenience, the process of forming the color filter substrate has been described through the process of FIGS. 3A to 3D, and the process of forming the display panel has been described with reference to FIG. 3E, but the color filter substrate and the display panel are sequentially formed in this way. It's obviously not what you should do.

Now, as shown in FIG. 3F, the first carrier substrate 110 on which the separation layer 120, the protective layer 130, and the color filter layer 170 are formed through the process of FIGS. 3A to 3D and shown in FIG. 3E As described above, the second carrier substrate 210 on which the display panel 200 is formed is aligned.

Next, as shown in FIG. 3G , the two aligned substrates are bonded. Conjugation can be made using OCA or OCR. The bonding of the substrate may be performed in any other manner known in the field of flexible display technology, and the process is not particularly limited in the present invention.

Now, as shown in FIG. 3H , the first carrier substrate 110 and the second carrier substrate 210 are separated. In this case, the first carrier substrate 110 and the second carrier substrate 210 may be simultaneously separated or sequentially separated, and when sequentially separated, the first carrier substrate 110 and the second carrier substrate 210 may be separated in an arbitrary order.

Meanwhile, when the first carrier substrate 110 is separated, the separation layer 120 may be separated together, thereby forming a flexible display device according to an embodiment of the present invention as shown in FIG. 2 .

The separation process is performed at room temperature, and for example, may be performed by a peeling method in which the first carrier substrate 110 and the second carrier substrate 210, which are glass substrates, are physically separated.

The peeling method includes, but is not limited to, a lift-off method or a peel-off method.

Meanwhile, in the embodiment of the present invention described above, a method for manufacturing a flexible OLED display device in which the display panel includes an OLED layer has been described, but the present invention is not limited thereto. For example, even when a flexible liquid crystal display device is manufactured by inserting a liquid crystal layer instead of an OLED layer, the manufacturing method of the flexible display device of the present invention may be used with changes within a range obvious to those skilled in the art.

It will be understood that the present invention can be implemented in variously modified forms without departing from the essential characteristics of the present invention as described above.

Therefore, the specified embodiments should be considered in an illustrative rather than a restrictive sense, the scope of the present invention is indicated in the claims rather than in the foregoing description, and all differences within the equivalent range are included in the present invention. will have to be interpreted.

100: flexible color filter 110: first carrier substrate
120: separation layer 130: protective layer
140: black matrix layer 150: buffer layer
160: colored layer 170: color filter layer
200: display panel 210: second carrier substrate
220: base film 230: TFT layer
240: OLED layer 250: encapsulation layer
260: touch sensor layer 300: adhesive layer

Claims (16)

protective layer;
a black matrix (BM) layer formed on the passivation layer and partitioning a pixel area;
a buffer layer formed in a pixel region on the passivation layer; and
As a flexible color filter comprising a colored layer formed on the buffer layer,
The BM layer comprises carbon black,
The flexible color filter in which the BM layer and the buffer layer are formed of the same material. The method of claim 1,
A ratio of the area of the buffer layer to the area of the pixel area is 1 to 40%. The method of claim 1,
A ratio of the area of the buffer layer to the area of the pixel area is 5 to 15%. delete delete delete The flexible color filter according to any one of claims 1 to 3; and
and a display panel coupled to the flexible color filter. The method of claim 7, wherein the display panel comprises:
base film;
a thin film transistor on the base film;
an organic light-emitting diode (OLED) on the thin film transistor; and
A flexible display device comprising an encapsulation layer on the OLED. The flexible display device of claim 8 , wherein the display panel further comprises a touch sensor layer on the encapsulation layer. forming a separation layer on the first carrier substrate;
forming a protective layer on the separation layer;
forming a black matrix (BM) layer partitioning a pixel area and a buffer layer in the pixel area on the passivation layer; and
As a method of manufacturing a flexible color filter comprising the step of forming a colored layer on the buffer layer,
The BM layer comprises carbon black,
The method of manufacturing a flexible color filter in which the BM layer and the buffer layer are formed of the same material. 11. The method of claim 10,
A method of manufacturing a flexible color filter wherein a ratio of an area of the buffer layer to an area of the pixel area is 1 to 40%. 11. The method of claim 10,
A method of manufacturing a flexible color filter wherein a ratio of an area of the buffer layer to an area of the pixel area is 5 to 15%. delete delete delete 13. A method for manufacturing a flexible color filter according to any one of claims 10 to 12;
combining the flexible color filter with a display panel formed on a second carrier substrate; and
and removing the first carrier substrate, the separation layer, and the second carrier substrate.

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