KR102370126B1 - Foldable Display - Google Patents

Abstract

The present invention relates to an ultra-thin display device that maintains a display function even when folded. A foldable display device according to the present invention includes: a lower film having a display element layer and a protective layer applied to cover the display element layer; an upper film having a cover film, a hard coating layer applied to the outermost surface of the cover film, a polarizing film applied to one side of the cover film, and a touch pattern layer formed on the inner surface of the cover film; And an optical adhesive for bonding the lower film and the upper film.

Description

Foldable Display {Foldable Display}

The present invention relates to an ultra-thin foldable display device that maintains a display function even when folded. In particular, the present invention relates to an ultra-thin display device having excellent flexibility, maintaining a display function even when folded so that both ends contact each other, and having excellent restoring force.

Recently, various flat panel display devices capable of reducing weight and volume, which are disadvantages of a cathode ray tube, have been developed. Such flat panel displays include a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), and an electroluminescence device (EL). there is.

Since the flat panel display device is thin and light in weight, it is widely used as a display means in a mobile communication terminal or a portable information processor. In particular, in portable or mobile devices, there is an increasing demand for a display panel that is thinner, lighter, and consumes less power.

An electroluminescent display device is in the spotlight as a display device most suitable for these needs. The electroluminescent device is largely divided into an inorganic electroluminescent device and an organic light emitting diode device according to the material of the light emitting layer, and it has advantages of fast response speed, high luminous efficiency, luminance and viewing angle by using a self-luminous device that emits light by itself. The organic light emitting diode display has an organic light emitting diode (OLED).

The organic light emitting diode includes an organic electroluminescent compound layer that emits light by an electric field, and a cathode and an anode facing each other with the organic electroluminescent compound layer interposed therebetween. The organic electroluminescent compound layer includes a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and an electron injection layer (Electron injection). layer, EIL). In the OLED, excitons are formed in the excitation process when holes and electrons injected into the cathode electrode and the cathode recombine in the light emitting layer (EML), and light is emitted due to energy from the excitons.

An organic light emitting diode display (OLED) using the characteristics of an organic light emitting diode, which is an electroluminescent device, includes a passive matrix type organic light emitting diode display (PMOLED) and an active matrix It is roughly classified into an Active Matrix type Organic Light Emitting Diode display (AMOLED) type. In addition, depending on the direction in which light is emitted, there are a top-emission method and a bottom-emission method.

In particular, a liquid crystal display device or a plasma display device has a limit in developing a self-luminous device having high flexibility and elasticity, and thus there is a limit in application as a flexible display device. However, since the organic light emitting diode display device is formed using an organic thin film, interest is focused on it as an optimal material that can be applied to a flexible display device by using the flexibility and elasticity characteristic of the organic thin film. An active matrix type flexible organic light emitting diode display (AMOLED) displays an image by controlling the current flowing through the organic light emitting diode using a thin film transistor (TFT).

An organic light emitting diode display device (simply referred to as an organic light emitting display device) will be described with reference to FIG. 1 . 1 is a cross-sectional view schematically showing the structure of an information processing organ employing a thin film type organic light emitting diode display device. Referring to FIG. 1 , a thin film type organic light emitting diode display (DIP) includes an organic light emitting element layer FL, a back panel BP attached to the base of the organic light emitting element layer FL, and an upper surface of the organic light emitting element layer FL. It has a structure in which a polarizing film (POL) attached to the polarizing film (POL), a touch panel film (TSP) disposed on the polarizing film (POL), and a cover substrate (CV) are sequentially stacked on the touch panel film (TSP).

In order to reduce the thickness of the organic light emitting display device, the thickness of the substrate supporting the display device should be thin. However, in order to satisfy the conditions for mass production in a manufacturing line for forming a currently used display device, a thickness of at least 0.5 mm must be maintained. Therefore, in order to mass-produce a thin film type organic light emitting display device, a method of first completing a display element on a manufacturing substrate having a thickness of 0.5 mm, separating the substrate, and reattaching the thin film type back panel is used.

The organic light emitting device layer FL includes a flexible base layer PI formed on a manufacturing substrate (not shown), a display layer ACT formed on the flexible base layer PI, and an adhesive layer ADH to protect the display layer ACT. and a passivation layer BA bonded on the display layer ACT through the After the organic light emitting device layer FL is completed, the flexible base layer PI of the organic light emitting device layer FL is separated from the manufacturing substrate, and a thinner back panel BP is attached thereto.

Additional device films for user convenience are further attached on the organic light emitting device layer FL. For example, a touch film (TSP) capable of inputting user information by directly touching the screen may be attached. The touch film TSP may include a first touch film TS1 having wiring layers arranged in a horizontal direction and a second touch film TS2 having wiring layers arranged in a vertical direction. Alternatively, both an electrically separated horizontal wiring layer and a vertical wiring layer may be formed on the first touch film TS1 , and a bridge wiring for electrically connecting necessary portions may be formed on the second touch film TS1 .

A cover substrate CV for protecting all the display elements is attached. In addition, a polarizing film (POL) may be attached to the upper surface of the cover substrate (CV) to prevent reflection of external light from interfering with viewing of an image expressed by the display device. The thin film type organic light emitting display device thus formed is combined with various information processing devices to make a final product. For example, the organic light emitting display device is combined as one device on the upper part of the information processing device using the frame FR. In this case, a part of the frame FT has a structure that covers the upper side portion of the display device. This part is usually the bezel area (BZ). The bezel region BZ is a region where the driving circuit unit is disposed and/or where connecting members for connecting the driving circuit unit and the display panel are installed, and includes a non-display region of the organic light emitting diode layer FL.

Although such a thin film type display device can achieve a thin film type display device by using a glass substrate having a relatively thick cover substrate (CV), it does not have the flexibility to respond to an external impact or bending stress. However, by disposing a flexible cover window having characteristics similar to those of the back panel BP instead of the cover substrate CV, it can be applied as a flexible display device.

With current technology, thin-film display devices have been developed up to flexible displays that can be bent to some extent. However, development of a foldable display capable of maintaining a display function even when the center of the display panel is folded so that two opposite sides of the display panel are in contact with each other has not been developed. That is, according to the technology developed so far, it is possible to sufficiently overcome the stress and maintain the display performance to the extent of being rolled or bent by about 90 degrees. However, it has not been developed to the extent that the display function can be maintained even when folded or rolled into a fairly small radius like paper or thin vinyl film.

In order to develop a foldable display capable of maintaining a display function even when it is folded or bent as described above, it is first necessary to configure the display device in an ultra-thin shape. With the conventional technology, a thin film type display device can be formed by bonding thin films. However, since a plurality of films are bonded together, it is difficult to manufacture a foldable display device thin enough to be folded. That is, it is impossible to manufacture an ultra-thin and foldable display device only by bonding various functional films formed in the thin film type used in the prior art.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a foldable display device having multiple functions with a single film without bonding a plurality of functional films. Another object of the present invention is to provide a foldable display device that maintains a display function even when folded by applying/stacking functional thin film layers on one base film.

In order to achieve the object of the present invention, a foldable display device according to the present invention includes a lower film, an upper film, and an optical adhesive for surface bonding the lower film and the upper film. As for the lower film, the protective layer which covers a display element layer and a display element layer is apply|coated. The upper film includes a cover film, a hard coating layer applied to the outermost surface of the cover film, a polarizing film applied to one side of the cover film, and a touch pattern layer formed on an inner surface of the cover film.

For example, in the upper film, a hard coating layer is applied to an outer surface of the cover film, a polarizing film is applied to an inner surface of the cover film, and a touch pattern layer is sequentially formed.

In one example, the upper film further includes a barrier layer applied to be interposed between at least one of between the cover film and the hard coating layer and between the cover film and the polarizing film.

For example, in the upper film, a polarizing film and a hard coating layer are sequentially applied on the outer surface of the cover film, and a touch pattern layer is formed on the inner surface of the cover film.

For example, the polarizing film includes an alignment film and a liquid crystal dye layer. The alignment layer is applied to one side of the cover film. And the liquid crystal dye layer is applied on the alignment layer.

The foldable display device according to the present invention is an ultra-thin foldable device by bonding a lower film having a display element stacked on a single film in the form of a thin film and an upper film having a functional element coated/stacked on a single film in the form of a thin film. A display device can be implemented. In particular, by forming a film-type polarizing plate, which has been an obstacle to the development of a foldable display device, into an ultra-thin polarizing film, it is possible to apply/stack functional elements on the inner and outer surfaces of a single film in the form of a thin film. Accordingly, the display device according to the present invention is ultra-thin, and thus the display function can be maintained even when the display surface is folded or rolled to overlap with a small radius.

1 is a cross-sectional view schematically showing the structure of an information processing device employing a thin film type organic light emitting diode display device;
2 is a cross-sectional view illustrating a structure of a foldable display device according to a first embodiment of the present invention;
3 is a cross-sectional view illustrating a structure of a foldable display device according to a second embodiment of the present invention;
4 is a cross-sectional view illustrating a structure of a foldable display device according to a third embodiment of the present invention;
5 is a cross-sectional view illustrating a structure of a foldable display device according to a fourth embodiment of the present invention;
6 is a cross-sectional view illustrating a structure of a cover film coated with a polarizing film in a foldable display device according to an embodiment of the present invention;

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals refer to substantially identical elements throughout. In the following description, if it is determined that a detailed description of a known function or configuration related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

Hereinafter, a structure of a foldable display device according to a first embodiment of the present invention will be described with reference to FIG. 2 . 2 is a cross-sectional view illustrating a structure of a foldable display device according to a first embodiment of the present invention.

Referring to FIG. 2 , the foldable display according to the first embodiment of the present invention includes a lower film UF on which display elements are formed and an upper film OF on which functional elements are formed. The lower film UF includes an ultra-thin rear film BF having a foldable flexibility and having a base function, and an organic light emitting device layer FL applied/laminated on the rear film BF.

The organic light emitting element layer FL has a structure in which elements for performing an image display function are coated/stacked. For example, it may include a flexible base layer PI, a display layer ACT, an adhesive layer ADH, and a protective layer BA. The display layer ACT is formed in the form of a thin film of various elements for performing a display function, and may include a thin film type organic light emitting diode arranged in a matrix manner and a thin film transistor for driving the organic light emitting diode. The flexible base layer PI is applied/laminated on the lower layer of the display layer ACT to protect and maintain interfacial adhesion with the rear film BF. The protective layer BA is applied/stacked on the display layer ACT to protect the display layer ACT from external foreign substances such as moisture and air. The passivation layer BA is preferably applied thereon so as to cover the entire display layer ACT. If necessary, an adhesive layer ADH for increasing interfacial adhesiveness may be further applied between the protective layer BA and the display layer ACT.

Various functional elements capable of performing additional functions to the display elements formed on the lower film UF are formed on the upper film OF. For example, a touch layer having a touch function capable of inputting user information by directly touching the screen may be formed. The touch layer may include a first touch pattern layer TF1 having wiring layers arranged in a horizontal direction and a second touch pattern layer TF2 having wiring layers arranged in a vertical direction. Alternatively, both an electrically separated horizontal wiring layer and a vertical wiring layer may be formed on the first touch pattern layer TF1 , and a bridge wiring for electrically connecting necessary portions may be formed on the second touch pattern layer TF2 .

Although not shown in the drawings, since the first touch pattern layer TF1 and the second touch pattern layer TF2 must be electrically insulated, it is preferable to further include an insulating layer therebetween. The touch layer may be formed by depositing and patterning a transparent conductive material. Alternatively, the transparent conductive material may be formed to have a touch pattern using a printing technique.

In addition, a polarizing film (CPOL) may be applied to prevent external light from being reflected. The polarizing film CPOL is preferably applied to the inner or outer surface of the cover film CF in the form of a thin film to be thinner and foldable than the polarizing film. In addition, it is preferable to apply the hard coating layer HC to the outermost surface among the outer surfaces of the cover film CF. The hard coating layer HC is preferably formed of a high-strength material layer to prevent the outer surface of the cover film CF from being cracked or scratched by external impact or friction.

The upper film OF and the lower film UF are surface-bonded to form a foldable display. It is preferable that the upper film (OF) and the lower film (UF) be adhered through the optical adhesive layer (PSA) as a medium so that the surfaces can be firmly adhered. To this end, it is preferable to apply an optical adhesive layer (PSA) to the lowermost surface of the upper film (OF).

In the foldable display device according to the first embodiment of the present invention, the lower film UF can be manufactured in a sufficiently foldable ultra-thin film state even with the thin film device forming equipment currently used. In order to form the upper film OF in a foldable ultra-thin state, it has a structure in which a hard coating layer HC is applied to the outer surface of the cover film CF. In addition, a polarizing film CPOL is applied to the inner surface of the cover film CF. In addition, the first touch pattern layer TF1 and the second touch pattern layer TF2 are sequentially stacked under the polarizing layer CPOL.

Here, as the cover film CF, a foldable film having a thickness of about 20 to 30 μm is used. The hard coating layer (HC) and the polarizing layer (CPOL) each have the form of a thin film applied to a thickness of 5 μm or less. In addition, the first touch pattern layer TF1 and the second touch pattern layer TF2 have a thin film shape with a total thickness of 5 μm or less.

In addition, the optical adhesive layer PSA may be applied in the form of a thin film on the lowermost layer of the upper film OF, that is, the lower portion of the second touch pattern layer TF2 in advance to adhere to the lower film UF. The optical adhesive layer (PSA) may be applied to a thickness of about 15 μm. As a result, the upper film (OF) has a thickness of 60 µm or less (50 to 60 µm) even if the overall thickness considers the optical adhesive layer (PSA), so that it can be configured as a single film having all functions as a foldable film. there is.

As such, the upper film (OF) in which the functions are integrated should not lose functionality even if it is freely bent or folded to the extent that both sides almost touch it. In particular, when the foldable state is reached, a phenomenon in which bending stress is concentrated in the edge region of the upper film OF occurs. As a result, cracks or cracks may occur in the first touch pattern layer TF1 or the second touch pattern layer TF2 .

In order to prevent this, the first touch pattern layer TF1 and the second touch pattern layer TF2 are preferably formed to be spaced apart from each other by a predetermined interval inward from the area of the cover film CF. That is, by forming the wiring pattern to have a smaller area than the polarizing film CPOL and be included therein, it is possible to prevent the edge portion from being damaged by bending stress. In addition, if necessary, a barrier layer is further applied to a thickness of about 1 to 2 μm on the lower layer of the first touch pattern layer TF1 or the second touch pattern layer TF2 to add touch pattern layers TF1 and TF2. can be protected with

Hereinafter, a structure of a foldable display device according to a second embodiment of the present invention will be described with reference to FIG. 3 . 3 is a cross-sectional view illustrating a structure of a foldable display device according to a second embodiment of the present invention. In the second embodiment of the present invention, the structure of the lower film UF is the same as that of the first embodiment. However, there is a difference in the structure of the upper film OF. Accordingly, descriptions of the same parts will be omitted and descriptions will be made focusing on parts with differences.

In the foldable display device according to the second embodiment of the present invention, the functional elements are formed on the upper film CF but are formed in the form of a thin film so as to be formed into a foldable ultra-thin film is the same as in the first embodiment. However, there is a difference in the laminated structure to which each functional thin film is applied, and if necessary due to the changed laminated structure, it may be necessary to further apply additional thin films.

In the foldable display device according to the second embodiment, a polarizing film CPOL is applied to the outer surface of the cover film CF. And, it has a structure in which the hard coating layer HC is applied to the outer surface of the polarizing plate CPOL. In addition, the first touch pattern layer TF1 and the second touch pattern layer TF2 are sequentially stacked on the inner surface of the cover film CF.

Here, as the cover film CF, a foldable film having a thickness of about 20 to 30 μm is used. The hard coating layer (HC) and the polarizing layer (CPOL) each have the form of a thin film applied to a thickness of 5 μm or less. In addition, the first touch pattern layer TF1 and the second touch pattern layer TF2 have a thin film shape with a total thickness of 5 μm or less.

In addition, the optical adhesive layer PSA may be applied in the form of a thin film on the lowermost layer of the upper film OF, that is, the lower portion of the second touch pattern layer TF2 in advance to adhere to the lower film UF. The optical adhesive layer (PSA) may be applied to a thickness of about 15 μm. As a result, the upper film (OF) has a thickness of 60 µm or less (50 to 60 µm) even if the overall thickness of the optical adhesive layer (PSA) is considered, so that it can be configured as a single film having all functions as a foldable film. there is.

Hereinafter, a structure of a foldable display device according to a third embodiment of the present invention will be described with reference to FIG. 4 . 4 is a cross-sectional view illustrating a structure of a foldable display device according to a third embodiment of the present invention. Also in the third embodiment of the present invention, the structure of the lower film UF is the same as that of the first and second embodiments. However, there is a difference in the structure of the upper film OF. Accordingly, descriptions of the same parts will be omitted and descriptions will be made focusing on parts with differences.

In the foldable display device according to the third embodiment of the present invention, the functional elements are formed on the upper film CF but are formed in the form of a thin film so as to be formed into a foldable ultra-thin film is the same as in the first and second embodiments. or similar However, there is a difference in the laminated structure to which each functional thin film is applied, and if necessary due to the changed laminated structure, it may be necessary to further apply additional thin films.

In the foldable display device according to the third embodiment, a barrier layer BL is applied to the outer surface of the cover film CF. The barrier layer BL functions to further prevent foreign substances from penetrating into the inside of the display device from the outside. It has a structure in which the hard coating layer HC is applied to the outer surface of the barrier layer BL. In addition, a polarizing film CPOL is applied to the inner surface of the cover film CF. In addition, the first touch pattern layer TF1 and the second touch pattern layer TF2 are sequentially stacked on the inner surface of the polarizing layer CPOL.

Here, as the cover film CF, a foldable film having a thickness of about 20 to 30 μm is used. Since the barrier layer BL is applied to a thickness of several thousand Å, the entire hard coating layer HC and the barrier layer BL may have a thickness of about 5 μm. The polarizing film (CPOL) has a thin film form applied to a thickness of 5 μm or less. In addition, the first touch pattern layer TF1 and the second touch pattern layer TF2 have a thin film shape with a total thickness of 5 μm or less.

In addition, the optical adhesive layer PSA may be applied in the form of a thin film on the lowermost layer of the upper film OF, that is, the lower portion of the second touch pattern layer TF2 in advance to adhere to the lower film UF. The optical adhesive layer (PSA) may be applied to a thickness of about 15 μm. As a result, the upper film (OF) has a thickness of 60 µm or less (50 to 60 µm) even if the overall thickness of the optical adhesive layer (PSA) is considered, so that it can be configured as a single film having all functions as a foldable film. there is.

Hereinafter, a structure of a foldable display device according to a fourth embodiment of the present invention will be described with reference to FIG. 5 . 5 is a cross-sectional view illustrating a structure of a foldable display device according to a fourth embodiment of the present invention. Also in the fourth embodiment of the present invention, the structure of the lower film UF is the same as that of the first to third embodiments. However, there is a difference in the structure of the upper film OF. Accordingly, descriptions of the same parts will be omitted and descriptions will be made focusing on parts with differences.

In the foldable display device according to the fourth embodiment of the present invention, the functional elements are formed on the upper film CF but are formed in the form of a thin film to form a foldable ultra-thin film is the same as in the first and second embodiments. or similar However, there is a difference in the laminated structure to which each functional thin film is applied, and if necessary due to the changed laminated structure, it may be necessary to further apply additional thin films.

The foldable display device according to the fourth embodiment has a structure in which a hard coating layer HC is applied to the outer surface of the cover film CF. In addition, the barrier layer BL is applied to the inner surface of the cover film CF. The barrier layer BL functions to further prevent foreign substances from penetrating into the inside of the display device from the outside. A polarizing film CPOL is applied to the inner surface of the barrier layer BL. In addition, the first touch pattern layer TF1 and the second touch pattern layer TF2 are sequentially stacked on the inner surface of the polarizing layer CPOL.

Here, as the cover film CF, a foldable film having a thickness of about 20 to 30 μm is used. The hard coating layer HC has a thickness of 5 μm or less. Since the barrier layer BL is applied to a thickness of about several thousand Å, it may have a thin film form in which the combined thickness of the polarizing film CPOL is applied to a thickness of about 5 μm. In addition, the first touch pattern layer TF1 and the second touch pattern layer TF2 have a thin film shape with a total thickness of 5 μm or less.

In addition, the optical adhesive layer PSA may be applied in the form of a thin film on the lowermost layer of the upper film OF, that is, the lower portion of the second touch pattern layer TF2 in advance to adhere to the lower film UF. The optical adhesive layer (PSA) may be applied to a thickness of about 15 μm. As a result, the upper film (OF) has a thickness of 60 µm or less (50 to 60 µm) even if the overall thickness of the optical adhesive layer (PSA) is considered, so that it can be configured as a single film having all functions as a foldable film. there is.

An important feature for making the upper film OF foldable in the present invention is to apply a polarizing film COPL having a polarization function to the cover film CF in the form of a thin film. A polarizing film (CPOL) formation structure according to the present invention will be described with reference to FIG. 6 . 6 is a cross-sectional view illustrating a structure of a cover film coated with a polarizing film in a foldable display device according to an exemplary embodiment of the present invention.

Referring to FIG. 6 , the cover film CF has a structure in which a polarizing film CPOL is applied to an inner surface or an outer surface thereof. In particular, the alignment layer AL is applied to one side of the cover film CF. And, it has a structure in which the liquid crystal dye layer LSL is applied on the alignment layer AL. In particular, the liquid crystal dye layer LSL includes liquid crystal molecules to which two dyes having different colors are attached. The liquid crystal molecules are aligned according to the direction of the alignment layer AL, and thus may have linear polarization properties.

As described above, since the polarizing film CPOL is completed by applying the liquid crystal dye layer LSL, the material and thickness of the cover film CF can be freely selected. In addition, since the stretching process is not required, shrinkage stress does not occur, which is advantageous for realizing an ultra-thin and foldable functional film. In particular, the alignment layer AL and the liquid crystal dye layer LSL have the form of a thin film applied to a thickness of about 2 μm.

In the prior art, a plurality of functional films are surface-bonded to form an upper film. On the other hand, according to the present invention, it may have a structure in which several functional thin films are applied on a single film. Accordingly, it is possible to manufacture an ultra-thin display device compared to the prior art. In addition, it is possible to provide a foldable display device that can be folded beyond a flexible property that can be simply bent.

Although not shown in the drawings, if necessary, a circularly polarizing film for further adding a half-wavelength delay or a half-wavelength delay function in addition to the linear polarization function may be further provided. When the circularly polarizing film is also formed using a liquid crystal dye layer, a polarizing film in the form of an ultra-thin film can be formed. Even when a plurality of liquid crystal dye layers are stacked as described above, the polarizing film may have a thin film form coated with a thickness of about 5 μm.

Those skilled in the art from the above description will be able to see that various changes and modifications can be made without departing from the technical spirit of the present invention. Accordingly, the present invention should not be limited to the contents described in the detailed description, but should be defined by the claims.

BP: Back panel CV: Cover substrate
FL: organic light emitting device layer PI: flexible base layer
ACT: display layer ADH: adhesive layer
BA: protective layer POL: polarizing film
TSP: touch panel film TS1: first touch panel film
TS2: second touch panel film FR: frame
TSB: Touch base film CG: Cover glass
UF: lower film OF: upper film
CF: Cover film BF: Back film
HC: hard coat layer BL: barrier layer
CPOL: Polarizing film PSA: Optical adhesive layer
TF1: first touch pattern layer TF2: second touch pattern layer
AL: alignment layer LSL: liquid crystal dye layer

Claims (7)

a lower film having a display element layer and a protective layer applied to cover the display element layer;
an upper film having a cover film, a hard coating layer applied to the outermost surface of the cover film, a polarizing film applied to one side of the cover film, and a touch pattern layer formed on the inner surface of the cover film; And
It comprises an optical adhesive for surface bonding the lower film and the upper film,
The touch pattern layer has a smaller area than the polarizing film,
Spaced apart from the inside of the cover film by a certain interval,
The polarizing film is
an alignment layer applied to the one side of the cover film; And
and a liquid crystal dye layer applied on the alignment layer,
The liquid crystal dye layer consists of liquid crystal molecules to which two dyes having different colors are attached,
The upper film further includes a barrier layer interposed between at least one of between the cover film and the hard coating layer and between the cover film and the polarizing film,
The cover film has a thickness of 20 ~ 30um,
The hard coating layer and the polarizing film each have a thickness of 5 μm or less,
The touch pattern layer has a thickness of 5 μm or less,
The upper film is a foldable display having a thickness of 50 ~ 60um.
The method of claim 1,
The upper film is
A foldable display in which the hard coating layer is applied to an outer surface of the cover film, the polarizing film is applied to an inner surface of the cover film, and the touch pattern layer is sequentially formed.
delete The method of claim 1,
The upper film is
A foldable display device in which the polarizing film and the hard coating layer are sequentially applied to an outer surface of the cover film, and the touch pattern layer is formed in an inner surface of the cover film.
delete delete The method of claim 1,
The optical adhesive is a foldable display having a thickness of 15 μm.

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