KR102601900B1 - Cover window and disaly device including the same - Google Patents

Abstract

The present invention relates to a cover window in which a copolymer having different contents of a low-stiffness monomer and a high-stiffness monomer is synthesized in a first region and a second region, and a foldable display device including the same. Since there is a difference in the content of low-stiffness monomers and high-stiffness monomers in the first region and the second region, foldable characteristics can be realized centered on the first region. Although the contents of the low-stiffness monomer and the high-stiffness monomer are different in the first region and the second region, the first region and the second region are composed of the same copolymer. Therefore, since the refractive index of the first region and the second region is the same, visibility due to the difference in refractive index does not occur at the interface between the first region and the second region. Therefore, even if the cover window of the present invention is applied to the surface of the display device, a beautiful appearance without visual distortion can be secured.
In addition, by covering the front and sides of the display panel with a cover window including multiple regions with the same refractive index and different stiffness or hardness, it is possible to provide a display device with good visibility and an attractive appearance without the cover window being detachable.

Description

Cover window and display device including the same {COVER WINDOW AND DISALY DEVICE INCLUDING THE SAME}

The present invention relates to a display device, and more specifically, to a cover window that has a different modulus for each region but has a substantially same refractive index so that it is not visible, and a display device including the same that can implement an attractive appearance.

As display technology develops, display devices such as Liquid Crystal Display (LCD) and Organic Light Emitting Device Display (OLED) are being applied to computer monitors, TVs, cell phones, and displays of smart devices. . These display devices largely include a display panel that displays an image. In order to prevent the display panel from being damaged by external pressure, a cover window made of tempered glass or plastic surrounds one side or the entire surface of the display panel. there is.

Among methods for bonding a cover window and a display panel, direct bonding is commonly used. The direct bonding method uses optically clear resin (OCR) or optically clear adhesive (OCA) to cure the OCR and bond the cover glass and display panel.

Figure 1 is a cross-sectional view schematically showing a display device in which a cover window is attached to a display panel using a direct bonding method according to the prior art. As shown in FIG. 1, the display device 1 includes a display panel 10, a cover glass 30 disposed outside the display panel 10, and the display panel 10 and the cover glass ( 20) and includes an adhesive layer 20 that is applied and cured. The adhesive layer 20 is typically an optically clear adhesive (OCA), and an optically clear resin (OCR) is used.

Recently, there is a demand for a foldable display device that implements touch and is flexible and bendable. Accordingly, the cover window 30, which conventionally used tempered glass as its main material, is also manufactured from plastic, a flexible material. FIG. 2 is a diagram schematically showing the configuration of a cover window 30 applied to a conventional foldable display device.

As shown in FIG. 2, the cover window 30 applied to a conventional foldable display device includes a soft region 34 made of a soft material, for example, a urethane-based polymer, and a hard material adjacent to the soft region 34. , for example, hard regions 32a and 32b made of polymethyl methacrylate (PMMA)-based or polycarbonate (PC)-based polymer are located. Since the modulus characteristics of the polymer materials located in the soft region 34 and the hard regions 32a and 32b are different, foldable characteristics can be implemented centered on the soft region 34.

The cover window 30 for implementing foldable characteristics is generally manufactured using double injection molding, a type of multi-component injection molding. First, for example, a urethane-based soft polymer is first injected by filling and holding pressure in an injection mold, and then a transparent yet hard polymer such as PMMA or PC is filled and held adjacent to the injected soft polymer to create a soft region and a hard region. An integrated cover window can be manufactured.

Based on high-precision mold processing technology such as double injection molding and injection molding technology, it is beginning to be applied to large products such as display devices and is being used to release high-quality products. However, in the conventional cover window 30 with foldable characteristics, the soft region 34 and the hard regions 32a and 32b are made of completely different materials. Due to the characteristics of the soft region 34 and the hard regions 32a and 32b, which are composed of different materials, there is bound to be a difference in refractive index. Therefore, image distortion due to refraction of light occurs at the interfaces 36a and 36b between the soft region 34 and the hard regions 32a and 32b, and this distortion causes the soft region 34 and the hard regions 32a and 32b. The interfaces 36a and 36b are visible, which has the disadvantage of not having an attractive appearance.

The present invention was proposed to solve the problems of the prior art described above, and the purpose of the present invention is to provide a cover window with no difference in refractive index between the first and second areas and a display device including the same.

Another object of the present invention is to provide a cover window and a display device including the same that can implement and secure an attractive appearance by preventing visibility at the interface between the first area and the second area.

According to one aspect of the present invention having the above-described object, the present invention provides a cover window in which the first region and the second region are composed of the same copolymer, but the copolymer has different contents of low-stiffness monomers and high-stiffness monomers. provides.

Since the first region and the second region have different moduli due to different contents of high-rigidity monomers and low-rigidity monomers, the first region functions as a folding region.

Although the contents of high-stiffness monomers and low-stiffness monomers in the first and second regions are different, they are composed of the same high-stiffness monomers and low-stiffness monomers, so the first and second regions and the boundary between them have the same refractive index. have it

According to another aspect of the present invention, the present invention provides a display device in which the above-described cover window is attached to a display panel.

Additionally, the present invention provides a display device in which a cover window including multiple regions having the same refractive index and different rigidity or hardness covers the front and side surfaces of the display panel.

The cover window according to the present invention uses a copolymer of the same monomer in the first and second regions, but low-stiffness monomer and high-stiffness monomer are mixed in different content ratios in the first and second regions, respectively.

As different ratios of low-stiffness monomers are mixed in the first and second regions, the modulus and elastic modulus are different, allowing foldable characteristics to be realized centered on the first region.

Although the moduli of the first region and the second region are different, since the first region and the second region are composed of a copolymer of the same monomer component, there is substantially no difference in the refractive index of the first region and the second region. . Since there is no difference in refractive index between the first area and the second area, it is possible to prevent the area from being recognized due to a difference in refractive index between two adjacent areas at the boundary between the first area and the second area, and to achieve an attractive appearance.

In addition, by covering the front and sides of the display panel with a cover window including multiple regions with the same refractive index and different stiffness or hardness, it is possible to provide a display device with good visibility and an attractive appearance without the cover window being detachable.

1 is a cross-sectional view schematically showing a display device in which a cover window is attached to a display panel by applying a direct bonding method according to the prior art.
Figure 2 is a diagram schematically showing the configuration and problems of a cover window configured to have a foldable function according to the prior art.
3A and 3B are schematic plan and cross-sectional views of a cover window according to the first embodiment of the present invention.
Figure 3c is a diagram schematically showing a state in which the cover window according to the first embodiment of the present invention is flexibly bent.
Figure 4 is a diagram schematically showing the composition of the copolymer constituting the first region and the second region of the cover window with a foldable function according to the first embodiment of the present invention.
5A and 5B are respectively schematic diagrams of a display device in which a cover window is disposed according to an exemplary embodiment of the present invention.
Figure 6 is a cross-sectional view schematically showing a display panel of a liquid crystal display device according to an exemplary embodiment of the present invention.
Figure 7 is a cross-sectional view schematically showing a display panel of an organic light emitting diode display device according to another exemplary embodiment of the present invention.
8A and 8B are a schematic plan view and a cross-sectional view, respectively, of a cover window according to a second embodiment of the present invention.
Figure 9 is a photograph of the surface morphology of a copolymer synthesized by varying the contents of low-stiffness monomer and high-stiffness monomer according to an exemplary embodiment of the present invention.
Figure 10 is a graph measuring the refractive index of a copolymer synthesized by varying the contents of low-stiffness monomer and high-stiffness monomer according to an exemplary embodiment of the present invention.
11 is a schematic diagram of a display device including a cover window of the present invention.
Figure 12 is a schematic plan view of the cover window.
Figure 13 is a schematic diagram of a display device including a cover window of the present invention.

According to one aspect of the present invention, the present invention includes a first region; It includes second areas on both sides of the first area, wherein the first area and the second area have different stiffness or hardness, and the stiffness or hardness of the boundary between the first area and the second area gradually increases. Provides a changeable cover window.

For example, the surface morphologies of the first area, the second area, and the boundary between the first area and the second area may be different.

In one exemplary embodiment, the rigidity of the second region may be 2.5 to 7 times higher than the rigidity of the first region.

For example, the hardness of the first area may be 4B to 6B, and the hardness of the second area may be H or higher.

At this time, the refractive indices of the first region, the second region, and the boundary between the first region and the second region may all be the same.

The rigidity of the first region may be 2.5 to 7 times higher than that of the second region.

The hardness of the second region may be 4B to 6B, and the hardness of the first region may be H or higher.

In one exemplary embodiment, the first region and the second region each include a block copolymer composed of heterogeneous monomers having different rigidities, and the first region has a lower rigidity among the heterogeneous monomers. The molar ratio of the monomer having high rigidity may be greater than the molar ratio of the monomer having high rigidity, and in the second region, the molar ratio of the monomer having high rigidity among the heterogeneous monomers may be greater than the molar ratio of the monomer having low rigidity.

The first region and the second region each include a block copolymer composed of heterogeneous monomers having different rigidities, and the first region has a low rigidity with a molar ratio of monomers having high rigidity among the heterogeneous monomers. The molar ratio of the monomer having low rigidity may be greater than the molar ratio of the monomer having high rigidity among the heterogeneous monomers in the second region.

In addition, the present invention includes a first region and a second region on both sides of the first region, the first region and the second region have different stiffness or hardness, and the first region, the second region, and The surface morphology of the boundary between the first region and the second region provides different cover windows.

At this time, the refractive indices of the first region, the second region, and the boundary between the first region and the second region may all be the same.

For example, the first region and the second region each include a block copolymer composed of heterogeneous monomers having different rigidities, and the first region has a molar ratio of monomers having low rigidity among the heterogeneous monomers. is greater than the molar ratio of the monomer having high rigidity, and in the second region, the molar ratio of the monomer having high rigidity among the heterogeneous monomers may be greater than the molar ratio of the monomer having low rigidity.

The first region and the second region each include a block copolymer composed of heterogeneous monomers having different rigidities, and the first region has a low rigidity with a molar ratio of monomers having high rigidity among the heterogeneous monomers. The molar ratio of the monomer having low rigidity may be greater than the molar ratio of the monomer having high rigidity among the heterogeneous monomers in the second region.

In an alternative embodiment, the method further includes a third region located outside each of the second regions, and a fourth region located between the second and third regions, wherein the third region is located outside the fourth region. has a stiffness or hardness higher than that of the region, wherein the stiffness or hardness of the third region is higher than or equal to the stiffness or hardness of the second region, and the stiffness or hardness of the fourth region is higher than the stiffness or hardness of the first region. It may be the same.

According to another aspect of the present invention, the present invention includes a display panel; A display device including the above-described cover window located on one side of the display panel is provided.

Additionally, the present invention includes a display panel; A cover including first and second areas having a planar area corresponding to a side surface of the display panel, and a third area located between the first and second areas and having a planar area corresponding to a front surface of the display panel. A display device includes a window, and the third region has higher rigidity or hardness than the first and second regions.

The first to third regions may have the same refractive index.

The cover window may be located outside each of the first and second regions and cover a rear surface of the display panel, and may further include fourth and fifth regions having the same rigidity or hardness as the third region.

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

[First Embodiment]

FIGS. 3A and 3B are schematic plan and cross-sectional views of the cover window according to the first embodiment of the present invention, and FIG. 3C is a schematic diagram showing a flexible bending state of the cover window according to the first embodiment of the present invention. am. Figure 4 is a diagram schematically showing the composition of the copolymer constituting the first region and the second region of the cover window with a foldable function according to the first embodiment of the present invention.

As shown in these figures, the cover window 400 according to the first embodiment of the present invention includes a first area 410 and a second area 420a located on both sides adjacent to the first area 410. , 420b). Meanwhile, a folding region (FR) is defined in the cover window 400. Centered around the folding region (FR), a Y plane is perpendicular to the X-axis direction, which is the direction in which the folding region (FR) extends. -The cover window 400 is folded so that both ends of the axial direction are perpendicular to both the X-axis direction and the Y-axis direction. In FIG. 2A, the folding area FR is defined to extend along the minor axis direction of the cover window 400, that is, the X-axis direction. However, the folding area FR extends along the major axis direction of the cover window 400, i.e. It may extend along the Y-axis direction.

In an exemplary embodiment, the first region 410 corresponds to the folding region FR, and the second regions 420a and 420b correspond to unfolding regions on both sides of the folding region FR, respectively. . Each of the first region 410 and the second regions 420a and 420b is made of a block copolymer containing the same high-stiffness monomer and low-stiffness monomer. In other words, the low-stiffness monomer and the high-stiffness monomer, which are unit components of the copolymer constituting the first region 410 and the second region 420a and 420b, are composed of the same component.

However, the molar ratio of the low-rigidity monomer in the first region 410 is greater than the molar ratio of the low-rigidity monomer in the second regions 420a and 420b. That is, the first region 410 has a relatively large content of low-rigidity monomers compared to the second regions 420a and 420b, and the second regions 420a and 420b have a relatively high content of low-rigidity monomers compared to the first region 410. The content of rigid monomers is relatively high. Accordingly, the first region 410 has a lower modulus value than the second regions 420a and 420b, so that the first region 410 can function as a folding region FR.

In an exemplary embodiment, the low-stiffness monomer constituting the copolymer of the first region 410 and the second region 420a, 420b is polyurethane (PU), polybutylacrylate (PBA), polystyrene, and polybutadiene. , is a unit component of polymer composed of polyethylene and their copolymers. In addition, the high-rigidity monomer constituting the copolymer of the first region 410 and the second region 420a and 420b is composed of polymethyl methacrylate (PMMA), polycarbonate (PC), and copolymers thereof. It is a unit component of a polymer. For example, low-stiffness monomers and high-stiffness monomers may be arranged in a block state.

In one exemplary embodiment, the first region 410 and the second regions 420a and 420b may include a block copolymer composed of heterogeneous monomers having different rigidities. At this time, in the first region 410, the molar ratio of the low-rigidity monomer (monomer with low rigidity) among the heterogeneous monomers is higher than the molar ratio of the high-rigidity monomer (monomer with high rigidity). On the other hand, in the second regions 420a and 420b, the molar ratio of the high-rigidity monomer among the heterogeneous monomers is higher than the molar ratio of the low-rigidity monomer.

For example, the copolymer constituting the first region 410 and the second region 420a and 420b may be represented by the following formula (1).

[Formula 1]

(In Formula 1, A represents a unit component constituting a polymer selected from the group consisting of polyurethane, polybutylacrylate, polystyrene, polybutadiene, polyethylene, and copolymers thereof, and B is polymethyl methacrylate, Represents a unit component constituting a polymer selected from the group consisting of polycarbonate and copolymers thereof; m and n are the mole fractions of A and B, respectively, and m + n = 1).

At this time, m > n in the first area 410 and m < n in each of the second areas 420a and 420b.

In another exemplary embodiment, the copolymer in the first region 410 may be represented by Formula 2 below, and the copolymer in the second regions 420a and 420b may be represented by Formula 3 below.

[Formula 2]

[Formula 3]

(In Formula 2 and Formula 3, A represents a unit component constituting a polymer selected from the group consisting of polyurethane, polybutylacrylate, polystyrene, polybutadiene, polyethylene, and copolymers thereof, and B is polymethyl meta Represents a unit component constituting a polymer selected from the group consisting of crylate, polycarbonate, and copolymers thereof; In Formula 2, m1 and n1 are the mole fractions of A and B, respectively, and m1 + n1 = 1; In Formula 3 m2 and n2 are the mole fractions of A and B, respectively, where m2 + n2 = 1).

At this time, m1 > m2 and n1 < n2.

In one exemplary embodiment, m1, the molar ratio of the low-rigidity monomer in the first region 410, may be 0.6 to 0.95, and n1, the molar ratio of the high-rigidity monomer, may be 0.05 to 0.4. In addition, m2, the molar ratio of the low-rigidity monomers in the second regions 420a and 420b, may be 0.05 to 0.4, and n2, the molar ratio of the high-rigidity monomers, may be 0.6 to 0.95.

In this way, the content ratio of the low-rigidity monomer and the high-rigidity monomer is varied in the first region 410 and the second regions 420a and 420b of the cover window 400, so that the first region 410 and the second region 420b The modulus value can be adjusted in the areas 420a and 420b. That is, as the content of low-stiffness monomers, which are components of polymers composed of PU, PBA, polystyrene, polybutadiene, polyethylene, and their copolymers, increases, the modulus value decreases (first region), and in the copolymer, PMMA , the modulus value increases as the content of high-stiffness monomers, which are constituents of polymers composed of PC and their copolymers, increases (second region). Meanwhile, the boundary portions 430a and 430b between the first area 410 and the second areas 420a and 420b have a modulus value between the first area 410 and the second areas 420a and 42b.

Therefore, the first region 410 has a relatively high content of low-rigidity monomers, the second regions 420a and 420b have a relatively high content of high-rigidity monomers, and the first region 410 and the second regions 420a and 420b ) The surface morphologies of the boundaries 430a and 430b are different from each other.

The first region 410 has improved flexibility and excellent impact resistance, and the second regions 420a and 420b have excellent hardness, scratch resistance, and good stiffness. . In other words, the second areas 420a and 420b have higher rigidity or hardness than the first area 410. For example, the stiffness of the second areas 420a and 420b may be 2.5 to 7 times higher than that of the first area 410. Meanwhile, the hardness (pencil hardness) of the first area 410 may be 4B to 6B, and the hardness (pencil hardness) of the second areas 420a and 420b may be H or higher.

In this case, the boundary portions 430a and 430b between the first area 410 and the second areas 420a and 420b extend from the first area 410, which has low rigidity or hardness, to the second area 420a, which has high rigidity or hardness. The stiffness or hardness may change to become progressively stronger toward 420b).

As described above, the molar ratio of the low-stiffness monomer in the copolymer forming the first region 410 corresponding to the folding region FR is the low rigidity in the copolymer forming the second regions 420a and 420b. Because it is greater than the molar ratio of monomers, the first region 410 has a smaller modulus value than the second regions 420a and 420b.

Therefore, as shown in FIG. 3C, since the cover window 400 has a desired modulus value as a whole and the first region 410 corresponding to the folding region FR has a relatively small modulus value, the cover window 400 is folded around this. Actions can be implemented. In particular, when a polymer composed of a low-stiffness monomer and a polymer composed of a high-stiffness monomer are mixed without forming a copolymer, it is not only difficult to uniformly mix the two polymers, but also phase separation problems may occur. Therefore, when a cover window using a polymer that is simply a mixture of two polymers is applied to a display device, display quality may deteriorate. However, in the present invention, this problem does not occur because the high-stiffness monomer and the low-stiffness monomer form a copolymer.

As described above, the first region 410 and the second regions 420a and 420b located adjacent thereto have a content ratio of the low-stiffness monomer (A in Formula 1) and the high-stiffness monomer (B in Formula 1). Although there are differences, the first region 410 and the second regions 420a and 420b are both composed of the same components, a low-stiffness monomer and a high-stiffness monomer (see FIG. 4). Although there is a difference in the content of the low-stiffness monomer (A) and the high-stiffness monomer (B), it is a copolymer of the same components. Accordingly, the refractive index at the first region 410, the adjacent second regions 420a, 420b, and the boundaries 430a, 430b between the first region 410 and the second regions 420a, 420b is substantially same.

Since there is substantially no difference in the refractive index of the first region 410 and the second regions 420a and 420b located adjacent thereto, even if the modulus values are different, the first region 410 and the second regions 420a, 420b, Light is not refracted at the boundary portions 430a and 430b of 420b). On the other hand, when a polymer composed of a low-stiffness monomer and a polymer composed of a high-stiffness monomer are mixed without forming a copolymer, there may be a difference in the refractive index of the soft region and the hard region depending on the content ratio of the two polymers.

Since light is not refracted at the boundaries 430a and 430b between the first area 410 and the second areas 420a and 420b, visibility does not occur at the boundaries 430a and 430b due to light refraction. Additionally, because the image is not distorted due to refraction of light, a beautiful appearance can be achieved.

The first region 410 constituting the cover window 400 and the second regions 420a and 420b adjacent thereto may be made of a copolymer of a low-stiffness monomer and a high-stiffness monomer. For example, the low-stiffness monomer may be a unit component constituting a polymer selected from the group consisting of polyurethane, polybutylacrylate, polystyrene, polybutadiene, polyethylene, and copolymers thereof. The high-stiffness monomer may be a unit component constituting a polymer selected from the group consisting of polymethyl methacrylate, polycarbonate, and copolymers thereof.

Glass cell casting is a method of manufacturing a cover window 400 divided into a first region 410 and a second region 420a and 420b, in which unit components constituting a copolymer are injected between two sheets of glass and then polymerized. (glass cell casting) method may be applied. That is, between the two glasses, each region corresponding to the first region 410 and the second regions 420a and 420b located on both sides thereof contain low-rigidity monomers (for example, butyl) at different content ratios. Acrylates) and high-stiffness monomers (e.g. methyl methacrylate) are alternately injected. For example, more low-rigidity monomers than high-rigidity monomers are injected into the region corresponding to the first region 410, and more high-rigidity monomers than low-rigidity monomers are injected into the regions corresponding to the second regions 420a and 420b. Inject.

The unit components constituting each copolymer are injected into the regions corresponding to the first region and the second region between the glasses, and placed in an oven to perform a polymerization reaction. When the polymerization reaction is completed, demolding is performed to remove the glass located at the upper and lower portions, so that both sides of the first region 410, which has low rigidity and/or low hardness characteristics, has high rigidity and/or high hardness characteristics. A cover window 400 made of plastic in which the second areas 420a and 420b are integrated can be manufactured.

Next, a foldable display device to which a cover window according to the first embodiment of the present invention is applied will be described. FIG. 5A is a cross-sectional view schematically showing a foldable display device to which a cover window is applied according to an exemplary embodiment of the present invention. As shown in FIG. 5A, the foldable display device 100 largely includes a display panel 200, a cover window 400 located outside the display panel 200, a display panel 200, and a cover window ( 400) and includes an adhesive layer 300 interposed between them. The display panel 200 may include any display panel capable of displaying an image, such as a liquid crystal display panel or an organic light emitting display panel using organic light emitting diodes.

As described above, the cover window 400 has a first region 410 (see FIG. 4) and second regions 420a and 420b located on both sides of the first region (see FIG. 4), and contains a low-stiffness monomer. It can be manufactured by varying the content ratio of the high-stiffness monomer. In an optional embodiment, hard coating layers 452 and 454 to reinforce the cover window 400 may be located on the top and bottom of the cover window 400, respectively.

In general, the cover window 400 is located on the outermost part of the display device 100, and therefore requires wear resistance to prevent external scratches, including fingernails or touch pens. Therefore, impact resistance must be improved to prevent the cover window 400 from being broken by external impact. To this end, a first hard coating layer 452 and a second hard coating layer 454 of a hard type capable of achieving high hardness are formed on the upper and lower parts of the cover window 400, respectively. For example, the hard coating layers 452 and 454 can be manufactured using urethane acrylic resin, methacrylic resin, silsesquioxane compound, etc., and can be manufactured using roll-coating, spin-coating, dip-coating, flow-coating and It can be coated on the cover window 400 using a method such as spray-coating.

The adhesive layer 300 interposed between the display panel 200 and the cover window 400 may be an optically clear adhesive (OCA). The adhesive layer 300 may be made of acrylate-based resin, (meth)acrylate-based resin, siloxane-based resin, rubber-based resin, urethane-based resin, etc., and is disposed between the display panel 200 and the cover window 400, The cover window 400 is attached to the display panel 200.

Meanwhile, the foldable display device of the present invention may have a touch function, and Figure 5b shows a foldable display device where the touch panel 290, also called a touch screen panel, is located between the display panel 200 and the adhesive layer 300. It shows (100'). In Figure 5b, the touch panel 290 is an add-on type located on the top of the display panel 200, but the touch panel 290 is an on-cell type located inside the display panel 200. It may be an embedded type such as an (on-cell) type or an in-cell type.

As described above, the display panel 200 may be a liquid crystal display panel or an organic light emitting diode display panel. FIG. 6 is a cross-sectional view schematically showing a display panel 200 made of, for example, a transverse electric field type liquid crystal display panel. As shown in FIG. 6, the display panel 200 according to the first embodiment has a first substrate 201 and a second substrate 202 facing each other, and between these substrates 201 and 202. A liquid crystal layer 230 is interposed. The first substrate 201 and the second substrate 202 may be made of plastic, for example, polyimide, and a plurality of electrodes and wires are stacked on top of the first substrate 201.

Looking more specifically at the plurality of electrodes and wiring stacked on the top of the first substrate 201, a plurality of gate wiring (not shown) extends in one direction on the top of the first substrate 201, and these plurality of gate wirings (not shown) extend in one direction. A plurality of data wires 270 are formed in the second direction by crossing the gate wire (not shown) to define a plurality of pixel areas P. A gate pad (not shown) is connected to one end of the gate wire (not shown) to form a non-display area, and a data pad (not shown) is connected to one end of the data wire 270 to form a non-display area. .

The plurality of pixel regions (P) include a gate electrode 262, a gate insulating film 263, a semiconductor layer 266 including an active layer 266a and an ohmic contact layer 266b, and source and drain electrodes 272. , 274) is formed. The gate electrode 262 is connected to a gate wire (not shown) and is formed on the first substrate 201. On the gate wiring (not shown) and the gate electrode 262, a gate insulating film 263 is formed of an inorganic insulating material, which may be, for example, silicon oxide (SiOx) or silicon nitride (SiNx). .

An active layer 266a made of pure amorphous silicon is formed on the gate insulating film 263, and an ohmic contact layer 266b is formed on the active layer 266a, exposes the center of the active layer 266a, and is made of impurity amorphous silicon. It is done. The active layer 266a and the ohmic contact layer 266b form the semiconductor layer 266.

A source electrode 272 and a drain electrode 274 are formed on the semiconductor layer 266 and spaced apart from each other to expose the center of the active layer 266a. The source electrode 272 is located on the semiconductor layer 266 and extends from the data line 270, and the drain electrode 274 is located on the semiconductor layer 266 and spaced apart from the source electrode 272. The thin film transistor (Tr) is located in the switching area (TrA).

Additionally, a data wire 270 extending along the second direction is formed on the gate insulating film 263 and intersects the gate wire (not shown). The data wire 270 extends from the source electrode 272 of the thin film transistor (Tr) located in the pixel area (P). Meanwhile, although not shown in the drawing, a common wiring (not shown) is formed on the gate insulating film 263 along a second direction parallel to the data wiring 270 and intersects the gate wiring (not shown). In an alternative embodiment, the common interconnection (not shown) may be formed in parallel with the gate interconnection (not shown) and on the same layer as the gate interconnection (not shown).

Meanwhile, a first protective layer 264 is formed covering the data wiring 270, the source electrode 272, the drain electrode 274, and the common wiring (not shown). A drain contact hole 275 is formed in the first protective layer 264 to expose the drain electrode 274 of the thin film transistor (Tr). This first protective layer 264 may be an inorganic insulating film made of silicon oxide (SiOx) or silicon nitride (SiNx), or an organic insulating film made of photoacrylic. The first protective layer 264 prevents the ohmic contact layer 266b from being damaged during the process of forming the pixel electrode 276.

In addition, in each pixel region (P), a pixel electrode 276 as a first electrode electrically connected to the drain electrode 274 of the thin film transistor (Tr) through the drain contact hole 275 is provided with a first protective layer. (264) It is formed in phase. The pixel electrode 276 is made of a transparent conductive material and may have a plate shape within each pixel area (P). For example, the transparent conductive material may be indium-tin-oxide (ITO) or indium-zinc-oxide (IZO).

Although not shown in the drawing, a gate pad electrode and a data pad electrode made of the same transparent conductive material as the pixel electrode 276 are formed in the non-display area on the top of the first protective layer 264, and the gate pad electrode is the gate electrode. It is electrically connected to the gate pad through a pad contact hole (not shown), and the data pad electrode is electrically connected to the data pad through a data pad contact hole (not shown).

A second protective layer 280, which is a second interlayer insulating film, is formed on the pixel electrode 276. The second protective layer 280 may be an inorganic insulating film made of silicon oxide (SiOx) or silicon nitride (SiNx), or an organic insulating film made of photoacrylic.

Meanwhile, a common electrode 290 is formed on the second protective layer 280, which overlaps the plate-shaped pixel electrode 276 and has a plurality of slit-shaped holes (openings, 292). Like the pixel electrode 276, the common electrode 290 as the second electrode may be made of a transparent conductive material such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO). The common electrode 290 is formed on the entire display area where a plurality of pixel areas (P) are formed. When a voltage is applied between the pixel electrode 276, which may be a plate-shaped first electrode, and the common electrode 290, which may be a second electrode having an opening 292, a fringe field is formed to form liquid crystal. By being driven, transmission efficiency is improved and high-quality images are displayed.

Although not shown in the drawing, a black matrix, which is a light blocking member, is formed on the lower part of the second substrate 202, which may be a color filter substrate, and has an opening corresponding to each pixel area P, and the lower part of the black matrix and the black matrix A color filter layer is formed on the lower part of the second substrate 202 exposed through the opening. The color filter layer (not shown) includes red, green, and blue color filters corresponding to the pixel area (P). In addition, between the color filter layer (not shown) and the liquid crystal layer 230, an overcoat layer (not shown) made of a material such as polyimide, polyacrylate, polyurethane, etc. is formed to protect and flatten the surface of the color filter layer (not shown). More can be formed.

Meanwhile, a polarizing plate 210 that selectively transmits only specific light is attached to the outside of the second substrate 202. Although not shown in the drawing, a polarizing plate (not shown) is also attached to the outside of the first substrate 201. In addition, a backlight unit (not shown) that supplies light from the back of the transverse electric field type liquid crystal display panel 200 may be provided so that the difference in transmittance shown by the transverse electric field type liquid crystal display panel 200 is expressed externally. The cover window 400 and the display panel 200 are connected to each other through the adhesive layer 300 (see FIG. 5A) interposed between the polarizer 210 attached to the outside of the second substrate 202 and the cover window 400 (see FIG. 5A). is cemented.

Figure 7 is a cross-sectional view schematically showing a display panel of an organic light emitting diode display device according to another exemplary embodiment of the present invention. As shown in FIG. 7, the light emitting diode panel 500 includes a flexible substrate 501 and a light emitting diode (E) formed on the flexible substrate 501.

For example, the flexible substrate 501 may be a polyimide substrate. Since the flexible substrate 501 is not suitable for the formation process of the light emitting diode (E), the light emitting diode (E) is formed by attaching the flexible substrate 501 to a carrier substrate (not shown) such as a glass substrate. The formation process proceeds. The light emitting diode display panel 500 can be obtained by forming the light emitting diode (E) on the flexible substrate 501 and then separating the carrier substrate and the flexible substrate 501. A buffer layer 510 is formed on the flexible substrate 501, and a thin film transistor (Tr) is formed on the buffer layer 510. The buffer layer 510 may be omitted.

A semiconductor layer 522 is formed on the buffer layer 510. The semiconductor layer 522 may be made of an oxide semiconductor material or polycrystalline silicon. When the semiconductor layer 222 is made of an oxide semiconductor material, a light blocking pattern (not shown) may be formed under the semiconductor layer 222, and the light blocking pattern prevents light from entering the semiconductor layer 222. This prevents the semiconductor layer 222 from being deteriorated by light. Alternatively, the semiconductor layer 222 may be made of polycrystalline silicon, and in this case, both edges of the semiconductor layer 222 may be doped with impurities.

A gate insulating film 524 made of an insulating material is formed on the semiconductor layer 522. The gate insulating film 224 may be made of an inorganic insulating material such as silicon oxide or silicon nitride. A gate electrode 530 made of a conductive material such as metal is formed on the gate insulating film 224 corresponding to the center of the semiconductor layer 522. In FIG. 7 , the gate insulating film 424 is formed on the entire surface of the flexible substrate 501, but the gate insulating film 524 may be patterned to have the same shape as the gate electrode 530.

An interlayer insulating film 532 made of an insulating material is formed on the gate electrode 530. The interlayer insulating film 532 may be formed of an inorganic insulating material such as silicon oxide or silicon nitride, or an organic insulating material such as benzocyclobutene or photo-acryl. The interlayer insulating film 532 has first and second contact holes 534 and 536 exposing both sides of the semiconductor layer 522 . The first and second contact holes 534 and 536 are located on both sides of the gate electrode 530 and are spaced apart from the gate electrode 530 .

Here, the first and second contact holes 534 and 536 are also formed within the gate insulating film 524. Alternatively, when the gate insulating film 524 is patterned to have the same shape as the gate electrode 530, the first and second contact holes 534 and 536 may be formed only in the interlayer insulating film 532.

A source electrode 540 and a drain electrode 542 made of a conductive material such as metal are formed on the interlayer insulating film 532. The source electrode 540 and the drain electrode 542 are positioned spaced apart from each other around the gate electrode 530, and are provided on both sides of the semiconductor layer 522 through the first and second contact holes 534 and 536, respectively. come into contact with

The semiconductor layer 522, the gate electrode 530, the source electrode 540, and the drain electrode 542 form the thin film transistor (Tr), and the thin film transistor (Tr) is a driving element. ) functions as

In one exemplary embodiment, the thin film transistor (Tr) is a coplanar ( It has a coplanar structure. In another exemplary embodiment, the thin film transistor Tr may have an inverted staggered structure in which a gate electrode is located at the bottom of the semiconductor layer and a source electrode and a drain electrode are located at the top of the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon.

Although not shown, gate wires and data wires intersect each other to define a pixel area, and a switching element connected to the gate wire and data wire is further formed. The switching element is connected to a thin film transistor (Tr), which is a driving element. In addition, a power wire is formed parallel to and spaced apart from the gate wire or the data wire, and a storage capacitor is further provided to maintain the voltage of the gate electrode of the thin film transistor (Tr), which is a driving element, constant during one frame. It can be configured.

A protective layer 550 having a drain contact hole 552 exposing the drain electrode 542 of the thin film transistor (Tr) is formed to cover the thin film transistor (Tr).

On the protective layer 550, a first electrode 560 connected to the drain electrode 542 of the thin film transistor (Tr) through the drain contact hole 552 is formed separately for each pixel area. The first electrode 560 may be an anode and may be made of a conductive material with a relatively high work function value. For example, the first electrode 560 may be made of a transparent conductive material such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO). .

Additionally, a bank layer 566 is formed on the protective layer 250 to cover the edge of the first electrode 260. The bank layer 566 exposes the center of the first electrode 560 corresponding to the pixel area.

An organic light-emitting layer 562 is formed on the first electrode 560. The organic light-emitting layer 562 may have a single-layer structure of an emitting material layer made of a light-emitting material. In addition, in order to increase light emission efficiency, the organic light emitting layer 562 includes a hole injection layer, a hole transport layer, a light emitting material layer, and an electron transport layer sequentially stacked on the first electrode 560. It may have a multi-layer structure of an electron transporting layer and an electron injection layer.

A second electrode 564 is formed on the flexible substrate 501 on which the organic light emitting layer 562 is formed. The second electrode 564 is located in front of the display area and is made of a conductive material with a relatively low work function value and can be used as a cathode. For example, the second electrode 564 may be made of any one of aluminum (Al), magnesium (Mg), and aluminum-magnesium alloy (AlMg). The first electrode 560, the organic light emitting layer 562, and the second electrode 564 form a light emitting diode (E).

An encapsulation film 570 is formed on the second electrode 564 to prevent external moisture from penetrating into the light emitting diode (E). The encapsulation film 570 may have a stacked structure of a first inorganic insulating layer 572, an organic insulating layer 574, and a second inorganic insulating layer 576, but is not limited to this. Additionally, a polarizing plate (not shown) may be attached to the encapsulation film 570 to reduce external light reflection. For example, the polarizer may be a circular polarizer.

Referring again to FIG. 5A , the cover window 400 is located on the top of the display panel 200 and is bonded to the display panel 200 through the adhesive layer 300. As shown in FIG. 4, the cover window 400 includes a first area 410 and second areas 420a and 420b located on both sides of the first area 410.

A folding area FR is defined in the cover window 400. As described above, centering on the folding region FR, both ends of the X-axis direction, which is the extending direction of the folding region FR, and the Y-axis direction planarly perpendicular to The cover window 400 and the display panel 200 are folded in a vertical direction. The first area 410 corresponds to the folding area FR, and each of the second areas 420a and 420b corresponds to the unfolding area on both sides of the folding area FR.

Each of the first region 410 and the second regions 420a and 420b is made of a block copolymer containing the same high-stiffness monomer and low-stiffness monomer. For example, the copolymer may be represented by the above-described formulas 1 to 3.

In the first region 410, the molar ratio of the low-rigidity monomer is relatively large, and in each of the second regions 420a and 420b, the molar ratio of the high-rigidity monomer is relatively large. The first area 410 has a smaller modulus value than the second areas 420a and 420b. Accordingly, in the foldable display device 100 including the cover window 400, damage and deterioration of display quality due to the folding operation are prevented.

Additionally, although the first region 410 and the second regions 420a and 420b have different modulus characteristics, they have substantially the same refractive index. Therefore, no refraction of light occurs at the boundary portions 430a and 430b between the first region 410 and the second region 420a and 420b, so there is no visibility at the interface, and the image is not distorted, making it possible to achieve a beautiful appearance. there is.

[Second Embodiment]

8A and 8B are a schematic plan view and a cross-sectional view, respectively, of a cover window according to a second embodiment of the present invention. As shown in FIGS. 8A and 8B, the cover window 400' according to the second embodiment of the present invention defines first to third folding regions FR1, FR2, and FR3 that are spaced apart from each other. A Y-axis perpendicular to the The cover window 400' is folded in a direction where both ends are perpendicular to both the X-axis direction and the Y-axis direction.

In FIG. 8A, the first to third folding regions FR1, FR2, and FR3 are defined as extending along the minor axis direction of the cover window 400', that is, the X-axis direction. Alternatively, the first to third folding regions FR1, FR2, and FR3 may extend in the long axis direction of the cover window 400', that is, in the Y-axis direction.

The cover window 400' includes a first area 412, second areas 422 and 424 located on both sides of the first area 412, and third areas located outside the second areas 422 and 424. It includes areas 426 and 428, and a fourth area 414 and 416 between the second areas 422 and 424 and the third areas 426 and 228. The first region 412 and fourth regions 414, 416, which have a high content of low-stiffness monomers, and the second regions 422, 424, and third regions 426, 428, which have a high content of high-stiffness monomers, are adjacent to each other. They are arranged alternately.

That is, the first region 412 and the fourth region 414, 416 correspond to the first to third folding regions FR1, FR2, and FR3, respectively, and the second regions 422, 424 and The third regions 426 and 428 are unfolded regions between the first region 412 and the fourth regions 414 and 416, respectively, and an outer region of the fourth regions 414 and 416, respectively. corresponds to the area.

Each of the first to fourth regions is made of a copolymer containing the same low-stiffness monomer and high-stiffness monomer. In other words, the low-stiffness monomer and the high-stiffness monomer, which are unit components of the copolymer constituting the first to fourth regions, may be composed of the same component.

However, the molar ratio of the low-rigidity monomer in the first region 412 and the fourth region 414, 416 is the molar ratio of the low-rigidity monomer in the second region 422, 424 and the third region 426, 428. It is large compared to. That is, the first region 412 and the fourth region 414 and 416 have a relatively high content of low-rigidity monomer compared to the second region 422 and 424 and the third region 426 and 428. On the other hand, the second regions 422 and 424 and the third regions 426 and 428 have a relatively higher content of high-stiffness monomer than the first region 412 and the fourth regions 414 and 416. Therefore, the first area 412 and the fourth area 414, 416 have a lower modulus value than the second area 422, 424 and the third area 426, 428, so the first area 412 ) and the fourth regions 414 and 416 can function as a folding region (FR).

At this time, for example, the third areas 426 and 428 may have higher rigidity or hardness than the fourth areas 414 and 416. In one exemplary embodiment, the stiffness or hardness of the third regions 426 and 428 may be equal to or higher than that of the second regions 422 and 424. In addition, the rigidity or hardness of the fourth areas 414 and 416 may be higher than or equal to that of the first area 412.

For example, the low-stiffness monomer constituting the copolymer of the first region 412, the second region 422, 424, the third region 426, 428, and the fourth region 414, 416 is polyurethane ( It is a unit component of a polymer composed of PU), polybutylacrylate (PBA), polystyrene, polybutadiene, polyethylene, and their copolymers. In addition, the high-rigidity monomer constituting the copolymer of the first region 412, second region 422, 424, third region 426, 428, and fourth region 414, 416 is polymethylmethacrylic. It is a unit component of polymer composed of polycarbonate (PMMA), polycarbonate (PC), and their copolymers. For example, the unit components of the low-stiffness monomer and the high-stiffness monomer may be arranged in a block state.

For example, the copolymer constituting the first region 412, second region 422, 424, third region 426, 428, and fourth region 414, 416 is represented by the following formula (1) You can.

[Formula 1]

(In Formula 1, A represents a unit component constituting a polymer selected from the group consisting of polyurethane, polybutylacrylate, polystyrene, polybutadiene, polyethylene, and copolymers thereof, and B is polymethyl methacrylate, Represents a unit component constituting a polymer selected from the group consisting of polycarbonate and copolymers thereof; m and n are the mole fractions of A and B, respectively, and m + n = 1).

At this time, m > n in the first area 412 and the fourth area 414 and 416, and m < n in the second area 422 and 424 and the third area 426 and 428.

In another exemplary embodiment, the copolymer of the first region 412 and the fourth region 414, 416 is represented by Formula 2 below, and the copolymer of the second region 422, 424 and the third region 426, 428), the copolymer may be represented by the following formula (3).

[Formula 2]

[Formula 3]

(In Formula 2 and Formula 3, A represents a unit component constituting a polymer selected from the group consisting of polyurethane, polybutylacrylate, polystyrene, polybutadiene, polyethylene, and copolymers thereof, and B is polymethyl meta Represents a unit component constituting a polymer selected from the group consisting of crylate, polycarbonate, and copolymers thereof; In Formula 2, m1 and n1 are the mole fractions of A and B, respectively, and m1 + n1 = 1; In Formula 3 m2 and n2 are the mole fractions of A and B, respectively, where m2 + n2 = 1).

At this time, m1 > m2 and n1 < n2.

In one exemplary embodiment, m1, the molar ratio of the low-stiffness monomers of the first region 412 and the fourth region 414, 416, is 0.6 to 0.95, and n1, the molar ratio of the high-stiffness monomers, is 0.05 to 0.4. You can. In addition, m2, the molar ratio of the low-rigidity monomers in the second regions 422 and 424 and the third regions 426 and 428, may be 0.05 to 0.4, and n2, the molar ratio of the high-rigidity monomers, may be 0.6 to 0.95.

The molar ratio of the low-stiffness monomer is relatively large in each of the first region 412 and the fourth region 414, 416, and the high-stiffness monomer is present in each of the second regions 422, 424 and third regions 426, 428. The molar ratio of monomers is relatively large. Accordingly, the first area 412 and the fourth area 414 and 416 have a smaller modulus value than the second area 422 and 424 and the third area 426 and 428.

A low-stiffness monomer and a high-stiffness monomer are formed in the first area 412 and the fourth area 414, 416, and the second area 422, 424 and the third area 426, 428 of the cover window 400'. By varying the content ratio, the modulus values can be adjusted in the first region 412 and the fourth region 414 and 416, and the second region 422 and 424 and the third region 426 and 428. That is, as the content of the polymer constituents, which are low-stiffness monomers such as PU, PBA, polystyrene, polybutadiene, polyethylene, and their copolymers, increases, the modulus value decreases (first and fourth regions). , the modulus value increases as the content of the polymer constituents consisting of PMMA, PC, and their copolymers, which are high rigidity monomers in the copolymer, increases (second and third regions). Accordingly, the first region 412 and the fourth region 414, 416 have improved flexibility and excellent impact resistance properties, and the second region 422, 424 and the third region 426, 428 ) has excellent hardness, anti-scratch properties and good stiffness.

At this time, the ratio of the low-stiffness monomer and the high-stiffness monomer in each of the first region 412 and the fourth region 414 and 416 may be the same or different. For example, because the folding stress is most concentrated in the first folding region FR defined at the center of the cover window 400', the low-stiffness monomer ratio in the first region 412 is lower than that in the fourth region ( 414, 416). That is, the modulus value of the fourth area 414, 416 is greater than the modulus value of the first area 412, and is greater than the modulus value of the second area 422, 424 and the third area 426, 428. It can be small. In other words, the rigidity or hardness of the fourth areas 414 and 416 is higher than or equal to that of the first area 412.

The second areas 422 and 424 and the fourth areas 426 and 428 may also have different modulus values. For example, the low-stiffness monomer ratio in the second regions 422 and 424 may be greater than the low-stiffness monomer ratio in the third regions 426 and 428. That is, the modulus value of the third areas 426 and 428 may be greater than the modulus value of the second areas 422 and 424. In other words, the rigidity or hardness of the third areas 426 and 428 is higher than or equal to that of the second areas 422 and 424.

As described above, the low-stiffness monomer in the copolymer forming the first region 412 and the fourth region 414, 416, respectively, corresponding to the first to third folding regions FR1, FR2, and FR3 Since the molar ratio is greater than the molar ratio of the low-stiffness monomer in the copolymer forming the second region (422, 424) and the third region (426, 428), the first region (412) and the fourth region (414, 416) ) has a smaller modulus value than the second areas 422 and 424 and the third areas 426 and 428.

While the cover window 400' has a desired modulus value as a whole, the first region 412 and the fourth region 414, 416 corresponding to the first to third folding regions FR1, FR2, and FR3 have a relatively small modulus. Because it has a value, the folding operation can be implemented based on this. In addition, in the present invention, since a high-stiffness monomer and a low-stiffness monomer form a copolymer, it is possible to prevent difficulties in the mixing process that may occur when two polymers are simply mixed and deterioration in display quality due to phase separation.

In addition, the first area 412 and the fourth area 414, 416, and the second areas 422, 424 and the third areas 426, 428 located adjacent thereto, all have the same component and have low rigidity. It is composed of monomers and high-stiffness monomers. Although there is a difference in the content of the low-stiffness monomer and the high-stiffness monomer, the first to fourth regions (412, 414, 416, 422, 424, 426, and 428 are all copolymers of the same component. Therefore, the first region ( The refractive indices of the fourth regions 412 and 416 and the adjacent second regions 422 and 424 and third regions 426 and 428 are substantially the same.

Therefore, light is not refracted at the boundaries of the first region 412 and the fourth region 414, 416, and the second region 422, 424 and the third region 426, 428 due to the difference in refractive index, so that the interface There are no poets in In addition, since the image is not distorted due to refraction of light, a beautiful appearance can be achieved.

Although not shown, the cover window 400' according to the second embodiment of the present invention can be used in a foldable display device. That is, as explained with FIGS. 5A, 5B, 6, and 7, the cover window 400' is attached to the upper surface of the liquid crystal panel 200 or the light emitting diode panel 500 to display the foldable display device 100. , 100') can be achieved.

Hereinafter, the present invention will be described in more detail with reference to exemplary embodiments, but the present invention is not limited to the technical idea described in the following examples.

Example 1: High-stiffness PMMA and low-stiffness PBA's Cover according to content ratio window manufacturing

The contents of the unit components of high-rigidity polymethyl methacrylate (PMMA, refractive index 1.49) and low-rigidity polybutylacrylate (PBA, refractive index 1.46) were varied, injected into a designated area between two sheets of glass, and in each area. A polymerization process was performed on the injected unit components to prepare a copolymer in which the contents of high-stiffness PMMA and low-stiffness PBA components differed depending on the region. As shown in Figure 9, when the unit content ratio of high-stiffness PMMA was 80%, Lamellar phase separation, which is a property of hard polymers, was observed, but when the content of PMMA decreased to 20%, Sphere phase separation, which was a property of soft polymers, was observed. It was confirmed that copolymers with different moduli were synthesized depending on the content ratio of high-stiffness monomers and low-stiffness monomers.

In addition, the refractive index of the synthesized polymer was measured according to the content ratio of the components of high-stiffness PMMA and those of low-stiffness PBA. The refractive index was measured in the hard region where the content of the high-stiffness PMMA unit component was relatively high, the soft region where the content of the low-stiffness PBA unit component was relatively high, and the boundary region between the hard region and the soft region. The measurement results are shown in Figure 10 and Table 1 below. Although there was a difference in modulus due to a difference in the content ratio of low-stiffness monomer and high-stiffness monomer, it was confirmed that the refractive index was the same for all regions.

[Table 1]

Example 2: Cover according to the content ratio of high-stiffness PMMA and low-stiffness PU window manufacturing

The procedure of Example 1 was repeated except that polyurethane (PU, refractive index 1.512) was used instead of PBA as the low-stiffness monomer polymer. The refractive index was measured in the hard region where the content of the high-stiffness PMMA unit component was relatively high, the soft region where the content of the low-stiffness PU unit component was relatively high, and the boundary region between the hard region and the soft region. The measurement results are shown in Table 2 below. There was a difference in modulus due to a difference in the content ratio of low-stiffness monomer and high-stiffness monomer, but it was confirmed that there was no significant difference in refractive index in all regions.

[Table 2

Example 3: Cover according to the content ratio of high-stiffness PMMA and low-stiffness polystyrene copolymer window manufacturing

The procedure of Example 1 was repeated except that polystyrene-polybutadiene copolymer was used instead of PBA as the low-stiffness monomer polymer. The refractive index was measured in the hard region where the content of the high-stiffness PMMA unit component was relatively high, the soft region where the content of the low-stiffness polystyrene-polybutadiene unit component was relatively high, and the boundary region between the hard region and the soft region. The measurement results are shown in Table 3 below. There was a difference in modulus due to a difference in the content ratio of low-stiffness monomer and high-stiffness monomer, but it was confirmed that there was no significant difference in refractive index in all regions.

[Table 3]

Figure 11 is a schematic diagram of a display device including a cover window of the present invention.

As shown in FIG. 11, the display device 600 includes a display panel 640 and a cover window 630 that covers the front and side surfaces of the display panel 640.

The display panel 640 may be a liquid crystal display panel or an organic light emitting display panel, but is not limited thereto.

The cover window 630 includes first and second areas 610a and 610b covering the side surfaces of the display panel 640 and a third area 620a covering the front surface of the display panel 640. Additionally, the cover window 630 may further include fourth and fifth areas 620b and 620c that cover the rear surface of the display panel 640. For example, when the display panel 640 is a liquid crystal display panel and a backlight unit is located on the back of the display panel 640, the first and second areas 610a and 610b are on the sides of the display panel 640 and the backlight unit. and the fourth and fifth areas 620b and 620c may cover the backside of the backlight unit.

Although not shown, the cover window 630 may be attached to the display panel 640 using an adhesive layer.

Each of the first and second areas 610a and 610b has a planar area substantially equal to the side surface of the display panel 640, and the third area 620a is the front surface of the display panel 640, that is, the image display area. It has a planar area substantially equal to the surface.

For example, referring to FIG. 3A, in the cover window 400, the first area 410 and the second area 420a, 420b have a planar area corresponding to the display surface of the display panel and are used in the foldable display device. .

In contrast, the cover window 630 of FIG. 11 has the same third area 620a corresponding to the entire display surface of the display panel 640, and the first and second areas 610a and 610b are the third area 620a. ) is located on both sides of the

That is, referring to FIG. 12, which is a schematic plan view of the cover window, the first and second areas 610a and 610b surround the central third area 620a and are connected to the third area 620a, and the third area 620a is connected to the third area 620a. It surrounds the first and second areas 610a and 610b, and the fourth and fifth areas 620b and 620c are connected to the first and second areas 610a and 610b. At this time, the width (or planar area) of the third area 620a is larger than the first and second areas 610a and 610b and the fourth and fifth areas 620b and 620c, respectively.

Each of the first to fifth regions 610a, 610b, 620a, 620b, and 620c is made of a block copolymer containing the same high-stiffness monomer and low-stiffness monomer. In other words, the low-rigidity monomer and the high-rigidity monomer, which are unit components of the copolymer constituting the first to fifth regions 610a, 610b, 620a, 620b, and 620c, are composed of the same component.

However, the molar ratio of the low-rigidity monomer in the first and second regions 610a and 610b is greater than the molar ratio of the low-rigidity monomer in the third to fifth regions 620a, 620b and 620c. That is, the third to fifth regions 620a, 620b, and 620c have a relatively large content of high-stiffness monomer compared to the first and second regions 610a and 610b, and the first and second regions 610a, 610b) has a relatively high content of low-rigidity monomers compared to the third to fifth regions 620a, 620b, and 620c. Accordingly, the first and second regions 610a and 610b have lower modulus values than the third to fifth regions 620a, 620b, and 620c.

For example, the copolymer constituting the first to fifth regions (610a, 610b, 620a, 620b, and 620c) may be represented by the following formula (1).

[Formula 1]

(In Formula 1, A represents a unit component constituting a polymer selected from the group consisting of polyurethane, polybutylacrylate, polystyrene, polybutadiene, polyethylene, and copolymers thereof, and B is polymethyl methacrylate, Represents a unit component constituting a polymer selected from the group consisting of polycarbonate and copolymers thereof; m and n are the mole fractions of A and B, respectively, and m + n = 1).

At this time, m > n in the first and second areas 610a and 610b, and m < n in each of the third to fifth areas 620a, 620b, and 620c.

For example, m, the molar ratio of the low-rigidity monomers in the first and second regions 610a and 610b, may be 0.6 to 0.95, and n, the molar ratio of the high-rigidity monomers, may be 0.05 to 0.4. In addition, m, the molar ratio of the low-rigidity monomers in the third to fifth regions 620a, 620b, and 620c, may be 0.05 to 0.4, and n, the molar ratio of the high-rigidity monomers, may be 0.6 to 0.95.

In this way, the content ratio of the low-stiffness monomer and the high-stiffness monomer is varied in the first and second regions 610a and 610b and the third to fifth regions 620a, 620b and 620c of the cover window 630, Modulus values may be adjusted in the first and second regions 610a and 610b and the third to fifth regions 620a, 620b and 620c.

That is, in the copolymer, as the content of the low-stiffness monomer, which is a component of the polymer composed of PU, PBA, polystyrene, polybutadiene, polyethylene, and their copolymers, increases, the modulus value decreases (first and second regions 610a, 610b)), in the copolymer, as the content of high rigidity monomer, which is a component of the polymer composed of PMMA, PC, and their copolymers, increases, the modulus value increases (third to fifth regions 620a, 620b, 620c) . Meanwhile, the boundaries between the first and second areas 610a and 610b and the third and fifth areas 620a, 620b and 620c are the boundaries between the first and second areas 610a and 610b and the third and fifth areas, respectively. It has a modulus value between (620a, 620b, 620c).

Therefore, the first and second regions 610a and 610b have a relatively high content of low-stiffness monomers, the third to fifth regions 620a, 620b and 620c have a relatively high content of high-stiffness monomers, and the first and The surface morphology of the boundary between the two regions 610a and 610b and the third to fifth regions 620a, 620b, and 620c is different from each other.

The first and second regions 610a and 610b have improved flexibility and excellent impact resistance, and the third to fifth regions 620a, 620b and 620c have excellent hardness and scratch resistance. characteristics and good stiffness.

That is, the third to fifth regions 620a, 620b, and 620c have higher rigidity or hardness than the first and second regions 610a and 610b. For example, the stiffness of the third to fifth regions 620a, 620b, and 620c may be 2.5 to 7 times higher than that of the first and second regions 610a and 610b. Meanwhile, the hardness (pencil hardness) of the first and second regions 610a and 610b may be 4B to 6B, and the hardness (pencil hardness) of the third to fifth regions 620a, 620b, and 620c may be H or higher.

In this case, the boundary between the first and second areas 610a, 610b and the third to fifth areas 620a, 620b, 620c is stiffer than the first and second areas 610a, 610b, which have lower rigidity or hardness. Alternatively, the rigidity or hardness may change to gradually become stronger toward the third to fifth regions 620a, 620b, and 620c with high hardness.

When the cover window 630 covers the front and sides of the display panel 640 to provide an attractive appearance, if the cover window 630 is made of a single material, that is, a material with the same modulus (stiffness or hardness), the display panel 640 (640) The cover window 630 cannot be completely attached to the display panel 640 because force is concentrated on the curved portion of the edge.

However, in the present invention, the cover window 630 has a third area 620a having a high modulus value corresponding to the display surface of the display panel 640 and a low modulus value corresponding to the side surface of the display panel 640. Since it includes the first and second areas 610a and 610b, the above-described problem does not occur.

Additionally, since the first area 620a corresponding to the display surface of the display panel 640 has high hardness, damage to the display panel 640 due to external impact is prevented.

On the other hand, when the cover window is made of different materials to include parts with different modulus values, a problem occurs in which the boundary between the third area 620a and the first and second areas 610a and 610b is visible. . That is, a problem of boundary visibility occurs due to a difference in refractive index between the third area 620a and the first and second areas 610a and 610b.

However, in the present invention, the first and second regions 610a and 610b and the third region 620a located adjacent thereto are composed of a low-stiffness monomer (A in Formula 1) and a high-stiffness monomer (B in Formula 1). Although there is a difference in the content ratio, the first and second regions 610a and 610b and the third region 620a are all composed of the same components, low-rigidity monomer and high-rigidity monomer. Although there is a difference in the content of the low-stiffness monomer (A) and the high-stiffness monomer (B), it is a copolymer of the same components. Accordingly, the refractive index of the third region 620a, the adjacent first and second regions 610a and 610b, and the boundary between them is substantially the same.

Accordingly, the boundary visibility problem between each of the first and second areas 610a and 610b and the third area 620a at the curved portion of the edge of the display panel 640, that is, the cover window 630, is prevented.

Meanwhile, each of the fourth and fifth areas 620b and 620c is made of the same material as the third area 610a, and can effectively protect the back surface of the display panel 640.

However, as shown in FIG. 13, the cover window 630 includes only the third area 610a and the first and second areas 620a and 620b, and the first and second areas 620a and 620b are The side and back surfaces of the display panel 640 may be covered.

Although the present invention has been described above based on exemplary embodiments and examples of the present invention, the present invention is not limited to the technical ideas described in the above embodiments and examples. Rather, anyone skilled in the art to which the present invention pertains can easily make various modifications and changes based on the above-described embodiments and examples. However, the fact that all such modifications and changes fall within the scope of the present invention will become clearer through the scope of the attached patent claims.

100, 100' foldable display device 200, 500: display panel
400, 400' cover window
410, 412: first area 420a, 420b, 422, 424: second area
426, 428: Third area 414, 416: Fourth area
430a, 430b: border
FR, FR1, FR2, FR3: folding region

Claims (19)

a first region;
Comprising second areas on both sides of the first area,
The first region and the second region have different stiffness or hardness,
The stiffness or hardness of the boundary between the first region and the second region changes gradually,
Each of the first region and the second region includes a block copolymer composed of heterogeneous monomers having different rigidities, and the block copolymer is represented by the following formula (1),
(a) m > n in the first area and m < n in the second area, or (b) m < n in the first area and m > n in the second area.
[Formula 1]

(In Formula 1, A represents a unit component constituting a polymer selected from the group consisting of polyurethane, polybutylacrylate, polystyrene, polybutadiene, polyethylene, and copolymers thereof, and B is polymethyl methacrylate, Represents a unit component constituting a polymer selected from the group consisting of polycarbonate and their copolymers; m and n are the mole fractions of A and B, respectively, and m + n = 1)
According to claim 1,
A cover window in which surface morphologies of the first area, the second area, and the boundary between the first area and the second area are different.
According to claim 1,
A cover window wherein the rigidity of the second region is 2.5 to 7 times higher than that of the first region.
According to claim 1,
A cover window wherein the first area has a hardness of 4B to 6B, and the second area has a hardness of H or more.
According to claim 1,
A cover window wherein the refractive indices of the first area, the second area, and the boundary between the first area and the second area are all the same.
According to claim 1,
A cover window wherein the rigidity of the first region is 2.5 to 7 times higher than that of the second region.
According to claim 1,
A cover window wherein the hardness of the second area is 4B to 6B, and the hardness of the first area is H or higher.
delete delete a first area, and
Comprising second areas on both sides of the first area,
The first region and the second region have different stiffness or hardness,
The surface morphologies of the first region, the second region, and the boundary between the first region and the second region are different from each other,
Each of the first region and the second region includes a block copolymer composed of heterogeneous monomers having different rigidities, and the block copolymer is represented by the following formula (1),
(a) m > n in the first area and m < n in the second area, or (b) m < n in the first area and m > n in the second area.
[Formula 1]

(In Formula 1, A represents a unit component constituting a polymer selected from the group consisting of polyurethane, polybutylacrylate, polystyrene, polybutadiene, polyethylene, and copolymers thereof, and B is polymethyl methacrylate, Represents a unit component constituting a polymer selected from the group consisting of polycarbonate and their copolymers; m and n are the mole fractions of A and B, respectively, and m + n = 1)
According to claim 10,
A cover window wherein the refractive indices of the first area, the second area, and the boundary between the first area and the second area are all the same.
delete delete According to any one of claims 1 to 5, 10, and 11,
It further includes a third area located outside each of the second areas, and a fourth area located between the second and third areas, respectively,
The third region has a higher rigidity or hardness than the fourth region, the rigidity or hardness of the third region is higher than or equal to the rigidity or hardness of the second region, and the rigidity or hardness of the fourth region is higher than or equal to the rigidity or hardness of the fourth region. 1 Cover window with area stiffness equal to or higher than the alarm.
a display panel;
A display device including the cover window according to any one of claims 1 to 7, 10, and 11, located on one side of the display panel.
a display panel including a front surface that is an image display surface, a rear surface opposite to the front surface, and a side surface connecting the front surface and the rear surface;
First and second regions having a planar area corresponding to a side surface of the display panel and covering a side surface of the display panel, and a planar area located between the first and second regions and corresponding to a front surface of the display panel. A cover window including a third area covering the front of the display panel,
The third region has a higher rigidity or hardness than the first and second regions.
According to claim 16,
A display device wherein the first to third regions have the same refractive index.
According to claim 16,
The cover window is located outside each of the first and second regions and covers a rear surface of the display panel, and further includes fourth and fifth regions having the same rigidity or hardness as the third region. According to claim 16,
Each of the first region, the second region, and the third region includes a block copolymer composed of heterogeneous monomers having different rigidities, and the block copolymer is represented by the following formula (1),
(a) A display device where m > n in each of the first and second areas, and m < n in the third area.
[Formula 1]

(In Formula 1, A represents a unit component constituting a polymer selected from the group consisting of polyurethane, polybutylacrylate, polystyrene, polybutadiene, polyethylene, and copolymers thereof, and B is polymethyl methacrylate, Represents a unit component constituting a polymer selected from the group consisting of polycarbonate and their copolymers; m and n are the mole fractions of A and B, respectively, and m + n = 1)

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