KR102553373B1 - Optical cleared adhesive and foldable display device including the same - Google Patents

Abstract

A foldable display device according to an embodiment of the present specification includes a display panel for displaying images, a cover member on top of the display panel, and a protective film on top of the cover member, wherein the protective film includes an adhesive layer and an adhesive layer in direct contact with the cover member. It includes a protective layer on the top, and the adhesive layer has a shape in which a first area to which UV is irradiated and a second area to which UV is not irradiated are patterned. An adhesive layer in which a first region having strong adhesive force and a second region having weak adhesive force compared to the first region are patterned has strong adhesive force in a horizontal direction and weakened adhesive force in a vertical direction, thereby reducing folding rigidity of the foldable display device. If the protective film is damaged, it can be reattached.
Through this, it is possible to prevent the protective film from being peeled off from the cover member due to folding while maintaining the folding characteristics of the foldable display device. When the display quality of the foldable display is degraded due to this, the protective film can be peeled off and reattached.

Description

Optical adhesive layer for foldable display device and foldable display device including the same {Optical cleared adhesive and foldable display device including the same}

The present specification relates to a foldable display device, and more particularly, to an optical adhesive layer for a foldable display device having improved durability and a foldable display device including the same.

In recent years, as society has entered the information age in earnest, the display field that processes and displays a large amount of information has developed rapidly, and in response to this, various flat display devices have been developed. Be in the spotlight.

Specific examples of such a flat panel display device include a liquid crystal display device (LCD), a plasma display panel device (PDP), a field emission display device (FED), and an electroluminescence display. Electroluminescence Display device (ELD), Organic Light Emitting Diodes (OLED), and the like. These flat-panel display devices show excellent performance in thinning, lightening, and low power consumption, compared to existing cathode ray tube (Cathode Ray Tube) : It is rapidly replacing the CRT).

On the other hand, since such a flat panel display device uses a glass substrate to withstand high heat generated during a manufacturing process, there are limitations in imparting lightness, thinness, and flexibility.

Therefore, a flexible display device manufactured using a flexible material such as plastic instead of a conventional inflexible glass substrate to maintain display performance even when bent like paper is rapidly emerging as a next-generation flat panel display device.

Flexible display devices use plastic thin film transistor substrates instead of glass, so they can be unbreakable with high durability, bendable that can be bent without breaking, rollable that can be rolled up, and foldable folder. It can be divided into foldable, etc., and such a flexible display has advantages of space utilization, interior and design, and can have various application fields.

In particular, in recent years, research into a foldable display device that can be carried in a folded state and displays an image in an unfolded state has been actively conducted in order to realize a large area along with ultra-thin, light weight, and miniaturization.

Foldable display devices can be applied to various fields, such as TVs and monitors, as well as mobile devices such as mobile phones, ultra mobile PCs, electronic books, and electronic newspapers.

This foldable display device largely includes a display panel for realizing an image, a back plate positioned below the display panel to support the display panel, and a cover member positioned in front of the display panel to protect the display panel. and a protective film positioned in front of the cover member to protect the cover member.

Since the foldable display device must be capable of folding and unfolding operations, the cover member is formed of a relatively thin film or a thin glass capable of being folded.

However, the cover member in the form of a thin film or glass may be damaged by an external impact, resulting in deterioration in display quality or damage to the light emitting diode by being transferred to a component under the cover member, for example, a light emitting diode.

At this time, although the surface of the foldable display can be protected with a protective film for protecting the surface of the foldable display, the degree of damage to the protective film increases as the foldable display is folded.

In general, an optical adhesive layer is interposed between the display panel, the cover member, and the cover member and the protective film, so that the display panel, the cover member, and the protective film are integrally bonded and modularized.

The inventors of the present invention, if the protective film for protecting the surface of the foldable display is adhered to the cover member with an adhesive layer having a single adhesive force, when the adhesive force is low, the protective film is not stably attached to the cover member during folding and non-folding. and can be peeled off. In addition, it has been recognized that when the adhesive force is high, the folding rigidity of the foldable display device rapidly increases, and thus the foldable characteristics of the foldable display device are inevitably degraded. Specifically, when the folding rigidity of the protective film is increased, it becomes more resistant to impact applied to the surface of the protective film, but as the foldable display device is folded, it may be easily damaged, such as cracks. Conversely, when the folding characteristics of the protective member are increased, the attachment stability of the protective film is weakened as the foldable display device is folded, causing the protective film to separate from the cover member as the foldable display device is repeatedly folded.

Accordingly, the inventors of the present invention have invented an optical adhesive having a novel structure that can solve the two problems described above.

The tasks of the present specification are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

As described above, in order to achieve the object, a foldable display device according to an embodiment of the present invention includes a display panel on which images are implemented, and a cover member is positioned on top of the display panel and a protective film is positioned on top of the cover member. do. The protective film includes an adhesive layer directly in contact with the cover member and a protective layer on the adhesive layer, and the adhesive layer is patterned with a UV-irradiated first region and a UV-irradiated second region.

Specifically, the adhesive strength of the first region is stronger than that of the second region, and the width of the first region increases from the cover member side to the protective layer side.

Other embodiment specifics are included in the detailed description and drawings.

Embodiments according to the present specification include an adhesive layer in which a first region having a high adhesive force and a second region having a lower adhesive force than the first region are patterned on the protective film, compared to an adhesive layer that is not patterned and has a low adhesive force in a horizontal direction. Adhesion is strengthened. Through this, it is possible to prevent the protective film from being peeled off from the cover member due to folding while maintaining the folding characteristics of the foldable display by lowering the folding rigidity of the foldable display.

In addition, a first region having a high adhesive force to the protective film and a second region having a lower adhesive force than the first region are included in the patterned adhesive layer, so that the adhesive force in the vertical direction is weakened compared to an adhesive layer that is not patterned and has a high adhesive force. Through this, when the cover member is not protected due to damage to the protective film or when the display quality of the foldable display device is deteriorated due to scratches on the surface of the protective film, the protective film can be peeled off and reattached.

Effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a schematic diagram schematically illustrating a foldable display device according to an exemplary embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view of the display panel of FIG. 1 .
3A to 3B are schematic cross-sectional views of a protective film of a foldable display device according to an exemplary embodiment of the present invention.
4A to 4B are plan views schematically illustrating an adhesive layer of a protective film according to another embodiment of the present invention.
5 is a plan view schematically showing an adhesive layer of a protective film according to another embodiment of the present invention.
6 is a plan view schematically showing an adhesive layer of a protective film according to another embodiment of the present invention.
7 is a schematic diagram schematically illustrating a manufacturing process of an adhesive layer according to an embodiment of the present invention.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs. It is provided to fully inform the holder of the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are illustrative, so the present invention is not limited to the details shown. Like reference numbers designate like elements throughout the specification. In addition, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. When 'includes', 'has', 'consists of', etc. mentioned in this specification is used, other parts may be added unless 'only' is used. In the case where a component is expressed in the singular, the case including the plural is included unless otherwise explicitly stated.

In interpreting the components, even if there is no separate explicit description, it is interpreted as including the error range.

In the case of a description of a positional relationship, for example, when the positional relationship of two parts is described with '~on', '~upper', '~lower', 'next to', etc., 'right' Or, unless 'directly' is used, one or more other parts may be located between the two parts.

When an element or layer is referred to as “on” another element or layer, it includes all cases where another element or layer is directly on top of another element or another layer or other element intervenes therebetween.

Although first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another. Therefore, the first component mentioned below may also be the second component within the technical spirit of the present invention.

Like reference numbers designate like elements throughout the specification.

The size and thickness of each component shown in the drawings are shown for convenience of description, and the present invention is not necessarily limited to the size and thickness of the illustrated components.

Each feature of the various embodiments of the present invention can be partially or entirely combined or combined with each other, and as those skilled in the art can fully understand, various interlocking and driving operations are possible, and each embodiment can be implemented independently of each other. It may be possible to implement together in an association relationship.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram schematically illustrating a foldable display device according to an exemplary embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of the display panel of FIG. 1 .

As shown, the foldable display 100 includes a display panel 110 for realizing a large image, a touch panel (not shown) constituting a touch sensor (not shown), and a bag supporting the display panel 110. A back plate 120 and a cover member 130 to protect the display panel 110 and a protective film 140 to protect the cover member 130 are included.

A functional layer (not shown) may be included between the display panel 110 and the cover member 130, and the functional layer may include, for example, a polarizer, a phase delay plate, or a touch panel.

At this time, if the direction in the drawing is defined for convenience of explanation, the back plate 120 is positioned on the rear surface of the display panel 110 under the premise that the display surface of the display panel 110 faces forward, and the display panel 110 ) In front of the cover member 130 and the protective film 140 are located.

Here, the display panel 110 includes a liquid crystal display device (LCD), a plasma display panel device (PDP), a field emission display device (FED), an electroluminescent display device ( It may be made of one of Electroluminescence Display device (ELD) and Organic Light Emitting Diodes (OLED). However, it is preferable that OLED, which is a representative of flexible and foldable display devices capable of maintaining display performance even when bent like paper, is used as the display panel 110 .

OLED is a self-luminous device, and since it does not require a backlight used in a liquid crystal display device, which is a non-emissive device, it is possible to be lightweight and thin.

In addition, it has excellent viewing angle and contrast ratio compared to liquid crystal displays, is advantageous in terms of power consumption, can be driven at low DC voltage, has a fast response speed, is resistant to external shocks because the internal components are solid, and has a wide operating temperature range. It has advantages.

In particular, since the manufacturing process is simple, there is an advantage in that production costs can be significantly reduced compared to conventional liquid crystal display devices.

In the display panel 110 made of such an OLED, the substrate 101 on which the driving thin film transistor DTr and the light emitting diode E are formed is encapsulated by a protective film 102 .

Here, with reference to FIGS. 1 and 2 , a display panel 110 made of an OLED (hereinafter, referred to as an OLED panel) will be described in detail.

A semiconductor layer 104 is formed in the pixel region P on the substrate 101 . The semiconductor layer 104 is made of silicon, and its central portion is composed of an active region 104a constituting a channel, and source and drain regions 104b and 104c doped with high-concentration impurities on both sides of the active region 104a. However, it is not limited thereto, and the semiconductor layer 104 may be made of an oxide semiconductor.

A gate insulating film 105 is formed above the semiconductor layer 104 .

A gate electrode 107 corresponding to the active region 104a of the semiconductor layer 104 and a gate wiring extending in one direction may be formed above the gate insulating layer 105 .

In addition, a first interlayer insulating film 106a is formed on the entire upper surface of the gate electrode 107 and the gate wiring (not shown). At this time, the first interlayer insulating film 106a and the gate insulating film 105 under the first interlayer insulating film 106a expose the source and drain regions 104b and 104c located on both sides of the active region 104a, respectively. A layer contact hole 109 is provided.

Next, on the top of the first interlayer insulating film 106a including the first and second semiconductor layer contact holes 109, the source and drain regions 104b are spaced apart from each other and exposed through the first and second semiconductor layer contact holes 109. , 104c) are formed with source and drain electrodes 108a and 108b respectively contacting each other.

Further, a drain contact hole exposing the drain electrode 108b on the first interlayer insulating layer 106a exposed between the source and drain electrodes 108a and 108b and the source and drain electrodes 108a and 108b (108a and 108b) ( A second interlayer insulating film 106b having 112 is formed.

At this time, the semiconductor layer 104 including the source and drain electrodes 108a and 108b, the source and drain regions 104b and 104c in contact with the source and drain electrodes 108a and 108b, and the upper portion of the semiconductor layer 104 are formed. The gate electrode 107 forms a driving thin film transistor (DTr).

Meanwhile, although not shown in the drawing, a data line (not shown) intersecting with a gate line (not shown) to define the pixel region P is formed. Also, the switching thin film transistor (not shown) has the same structure as the driving thin film transistor DTr and is connected to the driving thin film transistor DTr.

In FIG. 2 , the switching thin film transistor (not shown) and the driving thin film transistor (DTr) have a semiconductor layer 104 made of a polysilicon semiconductor layer and a gate electrode 107 disposed on the semiconductor layer 104. Although shown as a co-planar type, it is not limited thereto, and is made of pure and impurity amorphous silicon, and is a bottom gate type in which the gate electrode 107 is disposed under the semiconductor layer 104. may be formed.

In addition, a first electrode 111 constituting an anode as a component constituting the light emitting diode E is formed in a region substantially displaying an image above the second interlayer insulating film 106b. The first electrode 111 may be made of, for example, a material having a relatively high work function value.

The first electrode 111 is electrically connected to the drain electrode 108b of the driving thin film transistor DTr through a contact hole. When the OLED display panel 110 is a top emission type, the first electrode 111 may be defined as including a transparent conductive material and an opaque conductive material having high reflectivity. For example, the first electrode 241 may include a transparent conductive oxide (TCO) such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO), silver (Ag), aluminum (Al), or gold (Au). ), molybdenum (Mo), tungsten (W), chromium (Cr), or alloys thereof.

Referring to FIG. 2 , the first electrode 111 is formed for each pixel region P, and a bank 119 is positioned between the first electrodes 111 formed for each pixel region P.

The bank 119 is formed in the area other than the light emitting area. Accordingly, the bank 119 has a bank hole exposing the first electrode 111 corresponding to the light emitting region. The bank 119 may be made of an inorganic insulating material such as silicon nitride (SiNx) or silicon oxide (SiOx) or an organic insulating material such as BCB, acrylic resin, or imide resin.

That is, the first electrode 111 is formed in a structure separated for each pixel region P by using the bank 119 as a boundary for each pixel region P.

An organic emission layer 113 is formed on the first electrode 111 .

Here, the organic light emitting layer 113 may be composed of a single layer made of a light emitting material, and to increase light emitting efficiency, a hole injection layer, a hole transport layer, an emitting material layer, and an electron It may be composed of multiple layers of an electron transport layer and an electron injection layer.

The organic light emitting layer 113 expresses red (R), green (G), and blue (B) colors. In a general method, red (R), green (G), and blue colors are displayed for each pixel area (P). (B) Separate organic materials (113a, 113b, 113c) emitting color are patterned and used.

A second electrode 115 forming a cathode is formed on the upper side of the organic light emitting layer 113.

In this case, the second electrode 115 includes a translucent metal film in which a metal material having a low work function is thinly deposited. In this case, the second electrode 115 may have a two-layer structure in which a transparent conductive material is thickly deposited on a translucent metal film.

Accordingly, light emitted from the organic light emitting layer 113 is driven toward the second electrode 115 in a top emission method.

Alternatively, the second electrode 115 may be formed of an opaque metal film, and light emitted from the organic light emitting layer 113 may be driven in a bottom emission method in which light is emitted toward the first electrode 111 .

When a predetermined voltage is applied to the first electrode 111 and the second electrode 115 according to the selected color signal, the OLED panel 110 generates holes injected from the first electrode 111 and the second electrode 115. Electrons provided from are transported to the organic light emitting layer 113 to form excitons, and when the excitons transition from an excited state to a ground state, light is generated and emitted in the form of visible light.

At this time, since the emitted light passes through the transparent second electrode 115 or the first electrode 111 and goes out, the OLED panel 110 implements an arbitrary image.

An encapsulation portion 102 in the form of a thin thin film is formed above the driving thin film transistor DTr and the light emitting diode E, and the OLED panel 101 is encapsulated through the encapsulation portion 102 . The encapsulation unit 102 may include at least two or more inorganic layers 102a to prevent external oxygen and moisture from penetrating into the OLED panel 110 . At this time, it is preferable that an organic layer 102b for supplementing the impact resistance of the inorganic layer 102a is interposed between the two inorganic layers 102a.

Meanwhile, the substrate 101 may be made of thin polyimide to have a flexible property. Since the substrate 101 made of thin polyimide is not suitable for forming a component such as a thin film transistor (DTr), in a state in which the substrate made of polyimide is attached to a carrier substrate such as a glass substrate, the thin film transistor (DTr) and Proceed with the formation process of the same component. Thereafter, the OLED panel 110 may be manufactured by separating the carrier substrate and the substrate made of polyimide.

A functional plate (not shown) on the OLED panel 110 may include a touch panel. The OLED panel 110 and the touch panel may be bonded to each other through an adhesive layer (not shown) of the touch panel.

Here, although not shown, in a touch panel, a first touch film (not shown) formed with a first touch electrode (not shown) and a second touch film (not shown) formed with a second touch electrode (not shown) are spaced apart from each other and face each other. can be arranged to do so.

The first touch electrode (not shown) is deposited on the entire surface of the first touch film (not shown), and the first touch electrode (not shown) is made of indium-tin-oxide (ITO) or indium-zinc-oxide, which is a transparent conductive material. (IZO).

And, on the second touch film (not shown) facing the first touch film (not shown), the second touch electrode (not shown) is formed in the form of a bar spaced apart at a predetermined interval, and is made of aluminum (Al) or aluminum. It is made of metal materials such as alloy (AlNd), magnesium (Mg), gold (Au), and silver (Ag).

The first and second touch electrodes (not shown) constitute a touch sensor (not shown).

Therefore, when a predetermined input means such as a finger or a pen is brought into contact with a certain point on the first touch film (not shown), the first touch electrode (not shown) formed on the first touch film (not shown) and the second 2 The second touch electrode (not shown) formed on the touch film (not shown) is mutually energized, and after reading the voltage value changed by the resistance value at that position, the control device can find the positional coordinates according to the change in potential difference. . However, the above-described touch panel is exemplary, and is not limited thereto, and various types of touch panels may be used.

The OLED panel 110 bonded to the touch panel is integrally modularized through the cover member 130, the protective film 140, and the back plate 120. A cover member 130 capable of protecting the OLED panel 110 is attached to the front of the OLED panel 110 where images are implemented through an optical adhesive layer 131, and a protective film is attached to the front of the cover member 130. (140) is attached.

Hereinafter, the protective film 140 will be described in detail with reference to FIG. 3 .

The foldable display device 100 according to an exemplary embodiment of the present invention includes a display panel 110 on which images are displayed, and a cover member 130 is positioned above the display panel 110 .

The cover member 130 protects the display panel 110 from external impact and transmits light emitted from the display panel 110 so that an image displayed on the display panel 110 can be viewed from the outside.

Such a cover member 130, for example, polymethylmethacrylate (PMMA), polycarbonate (PC), cycloolefin polymer (COP), which has impact resistance and light transmission, It may be a film type formed of organic materials such as polyethylene terephthalate (PET), polyimide (PI), and polyaramid (PA), or may be formed of inorganic materials such as thin glass and sapphire.

Since the display panel 110 is too thin, the back plate 120 is attached to the rear surface of the display panel 110 to support the display panel 110. A metal material such as stainless steel (SUS) or polymethyl methacrylate (polymethyl metacrylate, PMMA), polycarbonate (PC), polyvinylalcohol (PVA), acrylonitrile-butadiene-styrene (ABS), polyethylene terephthalate , PET).

A protective film 140 protecting the cover member 130 may be disposed above the cover member 130 . The protective film 140 may include an adhesive layer 141 in direct contact with the cover member 130 and a protective layer 142 on the adhesive layer 141 . The protective film 140 may play a role of alleviating folding stress applied to the components below, improving the impact resistance of the cover member 130 and preventing scratches.

Here, the adhesive layer 141 may have a first region 141a irradiated with UV and a second region 141b not irradiated with UV.

The upper and lower portions of the first region 141a of the adhesive layer 141 may have different widths. That is, the width of the first region 141a of the adhesive layer 141 may increase from the cover member 130 side toward the protective layer 142 side.

The first region 141a irradiated with UV may have stronger adhesion than the second region 141b to which UV is not irradiated. Also, the first region 141a may have a higher modulus than the second region 141b. For example, the modulus of the first region 141a may be 10 ⁶ to 10 ⁷ Pa, and the modulus of the second region 141b may be 10 ³ to 10 ⁵ Pa.

That is, the adhesive layer 141 of the protective film 140 includes a first region 141a having a high adhesive force and a high modulus and a second region 141b having a small adhesive force and a low modulus compared to the first region 141a, The first region 141a has a shape in which the width increases toward the top.

Unlike the foldable display device 100 according to the present embodiment, if the cover member 130 and the protective layer 142 are bonded with an unpatterned adhesive layer, when the adhesive strength is low, the protective film 140 during folding and non-folding The silver cover member 130 and the peeling. Also, when the adhesive strength is high, the folding rigidity of the foldable display device rapidly increases. Accordingly, the foldable characteristics of the foldable display device are inevitably degraded rapidly.

However, in the case of the foldable display 100 according to the present embodiment, as described above, the first area 141a has a high adhesive strength to the protective film 140 and the second area has a lower adhesive strength than the first area 141a. Since the adhesive layer 141 patterned with (141b) is included, the adhesive force in the horizontal direction is strengthened compared to the adhesive layer that is not patterned and has a low adhesive force, thereby lowering the folding rigidity of the foldable display device, thereby maintaining the folding characteristics of the foldable display device. However, it is possible to prevent the peeling of the protective film 140 from the cover member 130 due to folding.

In addition, the protective film 140 includes an adhesive layer 141 patterned with a first region 141a having a high adhesive force and a second region 141b having a lower adhesive force than the first region 141a. Compared to the adhesive layer with high adhesive strength, the adhesive strength in the vertical direction is weakened, so the protective film 140 is damaged and the cover member 130 cannot be protected, or the surface of the protective film 140 is scratched, resulting in display quality of the foldable display. When this is lowered, the protective film 140 may be peeled off and reattached.

At this time, the first region 141a of the adhesive layer 141 having stronger adhesive force than the second region 141b has a shape in which the width increases from the cover member 130 to the protective layer 142 as described above. Therefore, when the protective film 140 is peeled from the cover member 130, the adhesive layer 141 can be removed cleanly without leaving any residue on the cover member 130.

4A to 4B are plan views schematically showing an adhesive layer of a protective film according to another embodiment of the present invention, and FIG. 5 is a plan view schematically showing an adhesive layer of a protective film according to another embodiment of the present invention. And Figure 6 is a plan view schematically showing the adhesive layer of the protective film according to another embodiment of the present invention.

The shape of the first region 141a of the adhesive layer 141 will be described with reference to FIGS. 4A to 6 .

The first region 141a of the adhesive layer 141 may be patterned in various shapes, and may be patterned in the shape of islands spaced apart from each other, as shown in FIGS. 4A and 4B. For example, the island shape can be circular or polygonal. Also, as shown in FIG. 5 , the first region 141a of the adhesive layer 141 may be patterned in a stripe shape. The stripe shape may be formed in a vertical or horizontal direction, and may be patterned in a shape that crosses each other. Referring to FIG. 6 , the first region 141a may be patterned into a shape including both an island shape and a stripe shape.

Figure 7 is a schematic diagram schematically showing a manufacturing process of the adhesive layer 141 according to an embodiment of the present invention.

As shown in FIG. 7, a mask manufactured by dividing the adhesive layer 141 into a first region 141a and a second region 141b and enabling UV irradiation to a portion corresponding to the first region 141a After positioning adjacent to the adhesive layer 141, UV is irradiated using a UV irradiation device 290.

At this time, the adhesive layer 141 may be made of acrylate-based, epoxy-based, polyimide-based, vinyl-based, etc., and is preferably made of OCA (Optical Cleared Adhesive).

In particular, the adhesive layer 141 includes an initiator such as Iracure #184 or Iracure #819 that reacts to UV, and when UV is irradiated, the first region 141a is cured while the density of the adhesive layer 141 itself is improved by UV curing. It becomes.

In this case, the upper and lower portions of the first region 141a may have different widths by adjusting the distance between the adhesive layer 141 and the mask and the UV irradiation angle.

That is, in the adhesive layer 141 according to the embodiment of the present invention, the first region 141a and the second region 141b are made of the same material, but the first region 141a and the second region 141b are Only the modulus and adhesion properties are varied.

Through this, even if the first region 141a and the second region 141b have different modulus and adhesion characteristics, visibility according to the material characteristics of the first region 141a and the second region 141b does not occur.

As described above, the adhesive layer 141 of the protective film 140 is patterned into a first region 141a having a strong adhesive force and a second region 141b having a weak adhesive force compared to the first region 141a, and the first region ( By increasing the width of 141a) from the side of the cover member 130 toward the protective layer, it is possible to prevent the protective film 140 from falling when folding by making the adhesive force in the horizontal direction and the adhesive force in the vertical direction different from each other, and the protective film 140 ) can be replaced if damaged.

A foldable display device according to various embodiments of the present disclosure can be described as follows.

A foldable display device according to an exemplary embodiment of the present invention includes a display panel, a cover member 130 on top of the display panel, and a protective film 140 on top of the cover member 130 . The protective film 140 includes an adhesive layer 141 in direct contact with the cover member 130 and a protective layer on the adhesive layer 141, and the adhesive layer 141 includes the UV-irradiated first region 141a and the UV-irradiated first region 141a. The second region 141b that is not covered may have a patterned shape.

In this case, the upper and lower widths of the first region 141a may be different from each other. That is, the width of the first region 141a may increase from the cover member 130 toward the protective layer 142 .

The adhesive force of the first region 141a may be stronger than that of the second region 141b, and the modulus of the first region 141a may be greater than that of the second region 141b. For example, the modulus of the first region 141a may be 10 ⁶ to 10 ⁷ Pa, and the modulus of the second region 141b may be 10 ³ to 10 ⁵ Pa.

The first region 141a of the adhesive layer 141 may have an island pattern. For example, island patterns can be circular or polygonal.

Also, the first region 141a of the adhesive layer 141 may have a stripe pattern and may include both an island pattern and a stripe pattern.

A functional layer may be further included between the display panel and the cover member 130, and the functional layer may include a polarizer, a phase delay plate, or a touch panel.

The protective film 140 according to an embodiment of the present invention may include a protective layer and an adhesive layer 141 directly contacting the protective layer and including a first region 141a and a second region 141b.

At this time, the first region 141a has a high adhesive force to enhance the vertical direction adhesive force, and the second region 141b has a lower adhesive force than the first region 141a to improve re-peelability by weakening the horizontal adhesive force. can have

That is, the adhesive layer 141 is patterned into a first region 141a and a second region 141b, and the adhesive strength of the first region 141a may be greater than that of the second region 141b. Also, the width of the first region 141a may increase as it is closer to the upper protective layer.

Although the embodiments of the present specification have been described in detail with reference to the accompanying drawings, the present specification is not necessarily limited to these embodiments, and may be variously modified and implemented without departing from the technical spirit. Therefore, the embodiments disclosed herein are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. Each feature of the various embodiments of the present invention can be partially or entirely combined or combined with each other, can be technically interlocked and driven in various ways by those skilled in the art, and each embodiment can be carried out independently of each other or together in a related relationship. may be carried out. The protection scope of the present invention should be construed according to the following claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

110: display panel
120: back plate
130: cover member
140: protective film
141: adhesive layer
141a: first area, 141b: second area
142: protective layer
190: mask
290: UV irradiation device

Claims (19)

display panel;
a cover member on an upper portion of the display panel; and
Including a protective film on the top of the cover member,
The protective film,
It includes an adhesive layer in direct contact with the cover member and a protective layer on the adhesive layer,
The adhesive layer is made of OCA (Optical Cleared Adhesive), and a first area to which UV is irradiated and a second area to which UV is not irradiated are patterned,
The foldable display device of claim 1 , wherein a width of the first region increases from a side of the cover member to a side of the protective layer. delete delete According to claim 1,
The first area has a stronger adhesive force than the second area. According to claim 1,
The first area has a higher modulus than the second area. According to claim 5,
The first area has a modulus of 10 ⁶ to 10 ⁷ Pa, and the second area has a modulus of 10 ³ to 10 ⁵ Pa. According to claim 1,
The first area is an island pattern foldable display device. According to claim 7,
The island pattern is a circular or polygonal foldable display device. According to claim 1,
The foldable display device of claim 1 , wherein the first area has a stripe pattern. According to claim 1,
The first area includes both an island pattern and a stripe pattern. According to claim 1,
The foldable display device further comprising a functional layer between the display panel and the cover member. According to claim 11,
The functional layer includes a polarizer, a phase retardation plate, or a touch panel. protective layer; and
An adhesive layer in direct contact with the protective layer, including a first area and a second area, and made of OCA (Optical Cleared Adhesive),
The first region has a higher adhesive force than the second region to strengthen the vertical direction adhesive force and the second region has a lower adhesive force than the first region to improve re-peelability by weakening the horizontal adhesive force,
The first region is a protective film for a display device, the width of which is widened as it is closer to the protective layer. delete delete According to claim 13,
The first region is a protective film for a display device having an island pattern. According to claim 16,
The island pattern is circular or polygonal protective film for a display device. According to claim 13,
The first region is a protective film for a display device having a stripe pattern. According to claim 13,
The first region is a protective film for a display device including both an island pattern and a stripe pattern.

Images