KR20170112441A - Fabrication Method for Flexible Display Device - Google Patents

Abstract

The present invention relates to a method of manufacturing a flexible display device in which a color filter substrate is manufactured by forming a separation layer on a carrier substrate and then a process is performed on the separation layer, and the carrier substrate is removed after bonding with the thin film transistor array substrate.

Description

Technical Field [0001] The present invention relates to a fabrication method of a flexible display device,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a flexible display device, and more particularly, to a method of manufacturing a flexible display device in which a process is performed on a carrier substrate.

Flexible display means a display that can bend, bend or speak without loss of properties, and technology development is taking place in the form of flexible LCD, flexible OLED and electronic paper.

In order to realize flexible display, various plastic substrates have been developed as flexible substrates replacing existing glass substrates, and substrates of various components constituting flexible displays have been replaced by glass substrates. As a specific example, a color filter substrate comprising a film substrate made of polyimide disclosed in Korean Patent No. 10-1174148 and a color filter portion formed on the film substrate, a flexible filter substrate disclosed in Korean Patent Laid-Open No. 10-2013-0047971 layer; A buffer layer applied over the entire upper surface of the flexible layer; A display element formed on an upper surface of the buffer layer; And a flexible organic light emitting diode display device which is attached to the back surface of the flexible layer and includes a back panel having elasticity and flexibility for supporting the display device.

 However, in the case of using a flexible substrate, it is difficult to precisely arrange fine elements on a bent substrate. To solve this problem, Korean Patent No. 10-12670688 discloses a method of bonding a film substrate to a carrier substrate made of glass, And the carrier substrate is removed.

However, since such a film substrate has a lower transition temperature than that of glass and has a high expansion ratio according to a temperature change, there is a problem that the layers stacked thereon may be destroyed or deformed.

Further, when a flexible display device is manufactured by separately forming a color filter substrate and a thin film transistor array substrate on a flexible substrate, a film substrate of a flexible substrate must be bonded by a transfer method, thereby causing a large alignment error .

Korean Patent No. 10-1174148 Korean Patent Publication No. 10-2013-0047971 Korean Patent No. 10-12670688

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problem of the prior art flexible display device manufacturing method, and in order to manufacture a flexible display device in which a color filter substrate and a thin film transistor array substrate are formed on separate flexible substrates, And a manufacturing method of a flexible display device capable of reducing an error.

Another object of the present invention is to provide a method of manufacturing a flexible display device including a color filter substrate capable of obtaining a fixed three-pattern pattern that is difficult to implement in a conventional plastic substrate, solving thermal instability, and applying a substrate film of various materials .

In order to solve such problems, the present invention provides a method for manufacturing a semiconductor device, comprising: forming a separation layer by applying a composition for forming a separation layer on a first carrier substrate; Applying a composition for forming a protective layer on the separation layer to form a protective layer; Forming a black matrix (BM) layer on the protective layer and forming a colored layer therebetween; Aligning and bonding the first carrier substrate on which the separation layer, the protective layer, the BM layer, and the coloring layer are formed, with a thin film transistor (TFT) array substrate; And removing the first carrier substrate. The present invention also provides a method of manufacturing a flexible display device.

The method of manufacturing a flexible display device of the present invention may further include the step of attaching the flexible base film to the surface of the separation layer on which the first carrier substrate has been removed.

The TFT array substrate may include a white organic light emitting diode (OLED).

The TFT array substrate may include a second carrier substrate, wherein after the aligning and bonding step, removing the second carrier substrate may further comprise removing the second carrier substrate. The first and second carrier substrates may be simultaneously removed.

The protective layer may be formed to cover the side surface of the isolation layer, and the protective layer may include at least one of an organic insulating layer and an inorganic insulating layer.

The method of manufacturing a flexible display device according to the present invention may further include forming a flattening layer by applying a composition for forming a flattening layer on the BM layer and the colored layer.

The alignment layer and the adhesion layer may be formed on the first carrier substrate on which the separation layer, the protective layer, the BM layer, and the coloring layer are formed, and the separation layer, the protective layer, the BM layer, It is preferable to align the first carrier substrate on which the layer is formed and the TFT array substrate with an alignment error of 5 mu m or less.

In the aligning and bonding step, the first carrier substrate on which the separation layer, the protective layer, the BM layer, and the coloring layer are formed may be adhered to the TFT array substrate using an optical adhesive film or an optical adhesive resin.

According to the manufacturing method of the flexible display device of the present invention, the manufacturing process of the color filter is performed on the glass substrate instead of the base film made of plastic, thereby solving the problem caused by thermal deformation of the conventional plastic substrate, A fixed tax of a pattern that can not be implemented in the field is possible.

Also, by aligning and combining the color filter substrate formed on the glass substrate with the thin film transistor array substrate formed on the glass substrate, the alignment error between the color filter substrate and the thin film transistor array substrate can be remarkably reduced.

In addition, since the glass substrate as the carrier substrate is removed at room temperature after joining the color filter substrate and the thin film transistor array substrate, and the base film is separately bonded, the problem of thermal deformation of the conventional plastic substrate is solved, It is possible to secure the advantage of being able to diversify without limitation.

1 is a cross-sectional view of a flexible display device according to an embodiment of the present invention.
FIGS. 2 to 11 are cross-sectional views illustrating a method of fabricating a flexible display device according to an exemplary embodiment of the present invention.

The present invention provides a method of manufacturing a flexible display device capable of fabricating fixed three patterns and minimizing misalignment including a flexible color filter substrate without limitation of the material of a plastic substrate.

Hereinafter, preferred embodiments of a flexible display device and a manufacturing method thereof according to the present invention will be described in detail with reference to the drawings. It is to be understood, however, that the drawings are exemplary only for illustrating the present invention, and the present invention is not limited thereto. Also, for ease of explanation, some of the elements may be exaggerated in the drawings, or may be omitted or omitted.

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

Referring to FIG. 1, a flexible display device according to an embodiment of the present invention includes a TFT + OLED substrate (TFT) in which a thin film transistor (TFT) and an organic light emitting diode (OLED) 200), a color filter (CF) substrate (hereinafter referred to as a CF substrate) 100, and an adhesive layer 300 for bonding the same.

In the flexible display device according to an embodiment of the present invention, the CF substrate 100 and the TFT + OLED substrate 200 are flexible substrates on which the necessary components are disposed on the flexible substrate films 110 and 210, respectively, A flexible display device in which two substrates (100, 200) are bonded together is provided. In addition, each of the components disposed on the flexible substrate film 110, 210 also provides flexibility characteristics for a flexible display device, if desired.

Specifically, the CF substrate 100 includes a base film 110, a separation layer 120, a protective layer 130, a black matrix (BM) layer 140, a colored layer 150, and a planarization layer 160 ) Are stacked in this order.

In the present invention, in order to provide a flexible CF substrate, at least one of the layers constituting the CF substrate 100, preferably the separation layer 120 or the protection layer 130, and more preferably the separation layer 120, Lt; / RTI >

As the material of the organic layer, a polymer material may be used. The polymer material may be, for example, polyacrylate, polymethacrylate (for example, PMMA), polyimide, polyamide, polyvinyl alcohol, polyamic acid polyamide resin, polyimide resin, polyimide resin, polymamic acid, polyolefin (e.g., PE, PP), polystyrene, polynorbornene, phenylmaleimide copolymer, polyazobenzene, A polymer such as polyphenylenephthalamide, polyester (e.g., PET, PBT), polyarylate, cinnamate polymer, coumarin polymer, phthalimidine polymer, A chalcone-based polymer, and an aromatic acetylene-based polymer.

The polymeric material may be one selected from the group consisting of a base film 110, a separation layer 120, a protective layer 130, a BM layer 140, a colored layer 150, a planarization layer 160, Lt; / RTI > For example, the same or similar polymer may be applied to each layer, or polyacrylate may be applied only to the separation layer 120, and the remaining layers may be materials known in the art.

Each layer constituting the flexible CF substrate 100 according to the present invention will now be described in detail.

The base film 110 may be any of those usually used for optical transparent films, but it is preferable to use a film excellent in flexibility, transparency, thermal stability, moisture barrier property, uniformity of phase difference, isotropy and the like.

The material of the base film 110 may be a polymeric material as described above or a commonly used polyethylene terephthalate, polyethylene, polystyrene, polycarbonate, polyimide, or the like.

The separation layer 120 is formed for peeling off the flexible CF substrate 100 and the TFT + OLED substrate 200 after the completion of the bonding of the flexible CF substrate 100 and the carrier substrate in the manufacturing process of the flexible display device of the present invention.

Therefore, the separation layer 120 should be separated from the carrier substrate by a physical force, and after the separation, the base film 110 is laminated. Therefore, the peeling force of the separation layer 120 with respect to the glass substrate may be 5 N / 25 mm or less, preferably the separation force of the separation layer 120 may be 1 N / 25 mm or less, more preferably 0.1 N / Do. That is, it is preferable that the separation layer 120 is formed of a material such that the physical force applied when the separation layer 120 is separated from the carrier substrate does not exceed 1 N / 25 mm, especially 0.1 N / 25 mm.

When the peeling force of the separating layer 120 is more than 1 N / 25 mm, the separating layer 120 may not be separated neatly when separated from the carrier substrate, and the separating layer 120 may remain on the carrier substrate. The protective layer 130, the BM layer 140, the colored layer 150, and the planarization layer 160 may be cracked.

Particularly, it is more preferable that the separating force of the separating layer 120 is 0.1 N / 25 mm or less, and in the case of 0.1 N / 25 mm or less, the curl generated in the film after peeling from the carrier substrate is more preferable Do. Curl does not cause any problem on the side of the flexible CF substrate, but it is advantageous to make it less so that the process efficiency can be lowered in the joining step, the cutting step and the like.

Here, the thickness of the separation layer 120 is preferably 10 to 1000 nm, more preferably 50 to 500 nm. If the thickness of the separation layer 120 is less than 10 nm, the uniformity of the separation layer may deteriorate, the pattern formation may be uneven, the peeling force may be locally increased to cause tearing, or curl may not be controlled after separation from the carrier substrate There is a problem. If the thickness exceeds 1000 nm, the peeling force is not lowered further, and the flexibility of the film is deteriorated.

The difference in surface energy between the separation layer 120 and the carrier substrate is preferably 30 to 70 mN / m, and the difference in surface energy between the separation layer 120 and the carrier substrate is preferably 10 mN / m or more. The separating layer 120 must be stably adhered to the carrier substrate until it is peeled from the carrier substrate in the manufacturing process of the flexible display device and easily peeled off or peeled off from the carrier substrate . When the surface energy of the separation layer 120 is adjusted to be 30 to 70 mN / m after peeling, the peeling force can be adjusted and the adhesion strength between the separation layer 120 and the adjacent protection layer 130 is secured, thereby improving the process efficiency . Further, when the surface energy difference between the separation layer 120 and the carrier substrate is 10 mN / m or more, it can be smoothly peeled off from the carrier substrate, and tearing and cracking can be prevented.

The protective layer 130 is encapsulated to cover both sides of the separation layer 120 as a layer for protecting the separation layer 120. The protective layer may be formed of the above-described organic layer, but may also be formed of an inorganic insulating film.

The colored layer 150 is a layer for implementing color for a color display. Typically, the red, green, blue, and white patterns are patterned. And a BM layer 140 serving as a light-shielding layer for blocking light. However, the coloring layer does not necessarily include all the red, green, blue, and white patterns, and may include only a pattern of any one of the colors depending on the color representation of the flexible display device.

On the other hand, when the external light reaches the coloring layer of each color, only the light having the wavelength of the corresponding color is transmitted and the light having the wavelengths of the remaining two colors is absorbed. Thus, the amount of incident light of external light can be effectively reduced, May be performed instead.

The planarization layer 160 is a layer for improving the flatness of the coloring layer 150 and correcting the level difference of the coloring layer 150. The material of the planarization layer 160 is not particularly limited in the present invention, and may be a polyacrylate, a polyimide, .

Although the thickness of each of the organic layers is not particularly limited in the present invention, it is preferable that the thickness of each organic layer is several micrometers (탆) or less for thinning of the flexible CF substrate and the flexible display to be applied.

Preferably, the flexible CF substrate 100 according to an embodiment of the present invention includes

A base film 110 made of a polyimide-based material and having a thickness of 10 to 100 mu m;

A separating layer 120 made of a polyacrylic material and having a thickness of 0.01 to 1.0 mu m;

A protective layer 130 of a polycycloolefin-based material and having a thickness of 0.5 to 5 占 퐉;

A colored layer 150 having a thickness of 0.5 to 5 占 퐉; And

And a planarization layer 160 made of a polyacrylic material and having a thickness of 0.5 to 5 占 퐉.

The TFT + OLED substrate 200 has a structure in which a base film 210, a TFT layer 220, an OLED layer 230, and an encapsulation layer 240 are sequentially stacked, . In addition, the TFT + OLED substrate 200 may be fabricated in any manner known in the art of flexible display technology.

The BM layer 140 and the coloring layer 150 pattern of the flexible CF substrate 100 and the TFT layer 220 and the OLED layer 230 of the TFT + OLED substrate 200 in the flexible display device of the present invention can be formed using a common film Unlike the case of using a type color filter, the color filter is precisely aligned with an alignment error of 5 占 퐉 or less. Regarding such alignment of the substrate, the manufacturing method of the flexible display device of the present invention will be described in more detail below.

An adhesive layer 300 for bonding two substrates is formed between the flexible CF substrate 100 and the TFT + OLED substrate 200. The adhesive layer 300 is composed of an optically clear adhesive (OCA) or an optically clear resin (OCR).

FIGS. 2 to 11 are cross-sectional views of the flexible display device according to an exemplary embodiment of the present invention.

A method of manufacturing a flexible display device according to an embodiment of the present invention includes aligning and bonding a flexible CF substrate that is formed on a carrier substrate and can form fixed three patterns and has no limitation on the material of the plastic substrate, The alignment error can be minimized by separating the post-carrier substrate.

First, as shown in FIG. 2, after the first carrier substrate 170 is prepared, a separation layer 120 is formed by applying a composition for forming a separation layer.

Although it is preferable to use a glass substrate as the first carrier substrate 170, other materials may be used without limitation. However, it is preferable that the material has heat resistance so as not to be deformed even at high temperatures, that is, to maintain flatness so as to withstand subsequent process temperatures.

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 and the like can be mentioned. Or 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 heat curing or UV curing alone, or a combination of thermal curing and UV curing. When the thermosetting is used, it can be heated by an oven, a hot plate, etc. The heating temperature and time may vary depending on the composition, but for example, the heat treatment may be performed at 80 to 250 ° C for 10 to 120 minutes.

Next, as shown in FIG. 3, a protective layer 130 is formed on the separated isolation layer 120 so that the composition for forming a protective layer is applied to cover the isolation layer.

As described above, the separation layer 120 may be peeled off by a physical force, and it is preferable that the protection layer is formed to surround both sides since the peeling force is very weak.

The coating method and the curing process of the composition for forming the protective layer are as described above.

Next, as shown in FIGS. 4 and 5, a BM layer 140 is formed on the protective layer 130, and red (R), green (G), blue (B) The BM layer 140 is formed on the protective layer 130 so as to partition a portion forming a pixel, and then a coloring layer forming composition for color representation is formed on the protective layer 130 And is formed by exposure, development and thermosetting in a predetermined pattern. The color constituting the coloring layer may be arbitrarily selected, and the order of formation of each color may be arbitrarily selected.

The coating method and the curing process of the BM layer 140 and the coloring layer 150 are as described above.

Meanwhile, in the process of forming the BM layer 140, alignment keys (not shown) for alignment with the TFT + OLED substrate 200 are formed together.

In addition, the order of forming the BM layer 140 and the colored layer 150 may be changed as needed. That is, it is also possible to form the BM layer 140 after patterning the colored layer 150 first.

Next, as shown in FIG. 6, the planarization layer forming composition is applied over the formed BM layer 140 and the colored layer 150 to form the planarization layer 160.

On the other hand, a TFT + OLED substrate 200 as shown in FIG. 7 is formed on the second carrier substrate 270 in a process different from that described with reference to FIGS. The TFT + OLED substrate 200 may be manufactured in any manner 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 270 is preferably a glass substrate similarly to the first carrier substrate 170, but it is not limited thereto and other materials may be used. Again, materials with heat resistance that are not deformed at high temperatures, i.e., capable of maintaining planarity, in order to withstand subsequent process temperatures for TFT and OLED manufacturing are desirable.

In addition, an alignment key (not shown) for alignment with the CF substrate is formed on the TFT + OLED substrate 200 in an arbitrary process in the manufacturing process. For example, an alignment key can be formed in a metal layer formation step for forming a wiring.

8, the separation layer 120, the protective layer 130, the BM layer 140, the colored layer 150, and the planarization layer 160 are formed through the processes of FIGS. 2 to 6 The TFT + OLED substrate 200 formed on the first carrier substrate 170 and the second carrier substrate 270 are aligned. In this case, the alignment is performed using the alignment key formed on the BM layer 140 of the first carrier substrate 170 and the alignment key formed on the metal layer of the TFT + OLED substrate 200, .

The alignment key may be formed at the outermost portion of the panel in the substrate or at the outermost portion of the panel that is the edge of the glass substrate.

Particularly, since the process of manufacturing the color filter on the first carrier substrate 170 and the process of manufacturing the TFT and the OLED array on the second carrier substrate 270 are usually performed by separate processes, To align the two substrates.

When the CF substrate formed on the film substrate, which is a flexible substrate, is adhered to the TFT + OLED substrate by a transfer method as in the prior art, the alignment error is about 500 μm. However, according to the embodiment of the present invention, the first carrier substrate 170 having the separation layer 120, the protective layer 130, the BM layer 140, the colored layer 150, and the planarization layer 160 is formed, Since the TFT + OLED substrate 200 formed on the second carrier substrate 270 is aligned without removing the first and second carrier substrates 170 and 270 which are glass substrates, alignment accuracy can be remarkably improved. Specifically, the alignment error can be reduced to about 5 μm, which is a level of 1/100.

Next, as shown in Fig. 9, the aligned two substrates are bonded. The bonding can be done using OCA or OCR. Adhesion of the substrate may be accomplished 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. 10, the first carrier substrate 170 and the second carrier substrate 270 are separated. At this time, the first carrier substrate 170 and the second carrier substrate 270 can be separated at the same time or sequentially, and when they are sequentially separated, they can be separated in an arbitrary order.

Particularly, the process of separating the first carrier substrate 170 from the separation layer 120 proceeds at room temperature. For example, the first carrier substrate 170, which is a glass substrate, is physically peeled off from the separation layer 120 Or the like.

The method of peeling may be a lift-off method or a peel-off method, but is not limited thereto.

The characteristics of the separation layer 120 such as the peeling force, thickness, and difference in surface energy with respect to the carrier substrate after peeling are as described in the detailed description of the structure of the flexible display device according to an embodiment of the present invention, The separation layer 20 is neatly separated without remaining on the carrier substrate, cracks do not occur, and curl can be controlled.

Next, as shown in FIG. 11, the base film 110 is bonded to the separation layer 120.

The base film 110 is flexible and can be suitably selected among the aforementioned materials.

Although not shown in the drawing, the base film 110 can be adhered to the separation layer 120 using an adhesive layer. Since the adhesive that can be used is a photo-curable adhesive and does not require a separate drying process after photo- The process is simple and productivity is improved. As the photocurable adhesive used in the present invention, the photocurable adhesive used in the field can be used without any particular limitation. For example, a composition comprising an epoxy compound or an acrylic monomer can be used.

In addition, in the photocuring of the adhesive layer, an electron beam, a proton beam, a neutron beam and the like can be used in addition to electromagnetic waves such as light rays such as far ultraviolet ray, ultraviolet ray, near ultraviolet ray and infrared ray, X- It is advantageous to cure by ultraviolet irradiation from the availability of the irradiation apparatus, the price, and the like.

As a light source for ultraviolet irradiation, a high-pressure mercury lamp, an electrodeless lamp, an ultra-high pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp or a black light may be used.

Meanwhile, in the embodiment of the present invention described above, a method of fabricating a flexible OLED display device by combining a TFT + OLED substrate and a CF substrate in which an OLED is formed on a TFT has been described, but the present invention is not limited thereto. For example, when a flexible liquid crystal display device is manufactured by inserting a liquid crystal layer between a TFT array substrate and a CF substrate in place of the OLED, a range obvious to those skilled in the art is changed to manufacture a flexible display device Can be used.

It will be appreciated that the invention may be embodied in various forms without departing from the essential characteristics thereof, as set forth in the foregoing description.

It is therefore to be understood that the specified embodiments are to be considered in an illustrative rather than a restrictive sense and that the scope of the invention is indicated by the appended claims rather than by the foregoing description and that all such differences falling within the scope of equivalents thereof are intended to be embraced therein It should be interpreted.

100: Color filter substrate 110: Base film
120: isolation layer 130: protective layer
140: black matrix layer 150: colored layer
160: planarization layer 170: first carrier substrate
200: TFT + OLED substrate 210: substrate film
220: TFT layer 230: OLED layer
240: sealing layer 270: second carrier substrate
300: adhesive layer

Claims (10)

Applying a composition for forming an isolation layer on the first carrier substrate to form a separation layer;
Applying a composition for forming a protective layer on the separation layer to form a protective layer;
Forming a black matrix (BM) layer on the protective layer and forming a colored layer therebetween;
Aligning and bonding the first carrier substrate on which the separation layer, the protective layer, the BM layer, and the coloring layer are formed, with a thin film transistor (TFT) array substrate; And
Removing the first carrier substrate;
Wherein the flexible display device comprises a flexible display device. The method according to claim 1,
Further comprising the step of attaching a flexible substrate film on a surface of the separation layer on which the first carrier substrate has been removed,
A method of manufacturing a flexible display device. The method according to claim 1,
The TFT array substrate includes a white organic light emitting diode (OLED)
A method of manufacturing a flexible display device. The method according to claim 1,
Wherein the TFT array substrate includes a second carrier substrate,
After the aligning and bonding step,
And removing the second carrier substrate.
A method of manufacturing a flexible display device. 5. The method of claim 4,
Wherein the first and second carrier substrates are simultaneously removed,
A method of manufacturing a flexible display device. The method according to claim 1,
Wherein the protective layer is formed to surround the side surface of the isolation layer,
A method of manufacturing a flexible display device. The method according to claim 1,
Wherein the protective layer comprises at least one of an organic insulating film and an inorganic insulating film,
A method of manufacturing a flexible display device. The method according to claim 1,
Applying a composition for forming a planarization layer on the BM layer and the colored layer to form a planarization layer;
Further comprising the steps of: The method according to claim 1,
The alignment layer and the adhesion layer may be formed on the first carrier substrate on which the separation layer, the protective layer, the BM layer, and the coloring layer are formed, and the separation layer, the protective layer, the BM layer, Aligning the first carrier substrate on which the layer is formed and the TFT array substrate,
A method of manufacturing a flexible display device. The method according to claim 1,
In the aligning and adhering step, the first carrier substrate, which is formed with the separation layer, the protective layer, the BM layer, and the coloring layer is formed using an optically clear adhesive (OCA) or an optically clear resin (OCR) And the TFT array substrate,
A method of manufacturing a flexible display device.

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