Display device

Abstract

A display device according to one embodiment of the present specification may include: a display panel; a cover layer on the display panel; and a bonding layer including a main bonding layer on the capping layer and a nitrogen-reactive bonding layer on the main bonding layer, in which a content of nitrogen atoms of the nitrogen-reactive bonding layer may be greater than a content of nitrogen atoms of the main bonding layer.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Korean Patent Application No. 10-2024-0027330, filed on February 26, 2024, which is hereby incorporated by reference in its entirety for all purposes. Technical Field

[0003] This specification relates to a display device. Background Art

[0004] With the development of the information society, various demands on display devices for displaying images are increasing, and various types of display devices such as liquid crystal display (LCD) devices and organic light emitting diode (OLED) display devices are applied.

[0005] Among display devices, self-luminous OLED displays offer advantages in that, because they do not require a separate backlight, they offer superior viewing angles and contrast ratios compared to LCDs, are lighter and thinner, and consume less power. Furthermore, OLED displays can be driven with low DC voltages, have fast response times, and are significantly less expensive to manufacture. Summary of the Invention

[0006] The present specification aims to provide a display device in which a bonding layer can be easily peeled from a base substrate to which the bonding layer is attached.

[0007] The present specification aims to provide a display device in which ultraviolet rays can be irradiated to peel a bonding layer from a base substrate without generating heat, thereby preventing conflict with high temperature conditions during reliability evaluation.

[0008] The purpose of this specification is not limited to the above-mentioned purpose, and other technical purposes can be inferred from the following embodiments.

[0009] A display device according to an embodiment of the present disclosure includes: a display panel; a cover layer on the display panel; and a bonding layer including a main bonding layer on the cover layer and a nitrogen-reactive bonding layer on the main bonding layer. The nitrogen-reactive bonding layer has a nitrogen content greater than that of the main bonding layer.

[0010] A display device according to another embodiment of the present disclosure includes: a display panel; a main bonding layer on the display panel; a cover layer on the main bonding layer; and a nitrogen-reactive bonding layer on the cover layer. The nitrogen-reactive bonding layer has a nitrogen atom (N) content greater than that of the main bonding layer.

[0011] A display device according to another embodiment of the present disclosure includes: a display panel; a first stretchable sheet on the display panel; a primary bonding layer on the first stretchable sheet; a second stretchable sheet on the primary bonding layer; and a nitrogen-reactive bonding layer on the second stretchable sheet. The nitrogen-reactive bonding layer has a nitrogen atom content greater than that of the primary bonding layer.

[0012] Details of other embodiments are included in the detailed description and accompanying drawings.

[0013] According to the embodiment of the present specification, since the nitrogen-reactive bonding layer is formed of the ultraviolet-reactive adhesive, reliability evaluation of the product at high temperature can be easily performed.

[0014] According to the embodiments of the present disclosure, since the nitrogen reactive bonding layer can be separated from the base substrate by the ultraviolet irradiation method, physical damage can be prevented from occurring at the edge portion of the base substrate.

[0015] According to the embodiments of the present disclosure, since the edge portion of the base substrate is not physically damaged, the base substrate can be reused, thereby significantly reducing the discard rate of the base substrate. Therefore, the display device can be manufactured or produced in an environmentally friendly manner.

[0016] However, effects obtainable from the present specification are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood from the following description by those skilled in the art to which the present specification pertains.

[0017] Although the embodiments have been described above with reference to the accompanying drawings, those skilled in the art will appreciate that the above-described technical configurations may be implemented in other specific forms without changing the technical spirit or essential features of the above-described technical configurations. Therefore, it should be understood that the above-described embodiments are illustrative and non-restrictive in all respects. In addition, the scope of the embodiments is indicated by the claims to be described below rather than by the specific embodiments. In addition, the meaning and scope of the claims and all changes or modifications derived from their equivalent concepts should be interpreted as being included within the scope of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a cross-sectional view illustrating a substrate, a bonding layer, and a film according to one embodiment of the present specification.

[0019] Figure 2 is shown for use in accordance with Figure 1 A cross-sectional view of a seed space peeled off at an edge portion between a substrate and a bonding layer.

[0020] Figure 3 It is shown that by heating Figure 2 Schematic diagram of the bonding layer being peeled off from the substrate.

[0021] Figure 4 It is shown that the UV reaction will be based on Figure 2 Schematic diagram of the bonding layer being peeled off from the substrate.

[0022] Figure 5 It is shown that the aqueous solution method will be based on Figure 2 Schematic diagram of the bonding layer being peeled off from the substrate.

[0023] Figure 6 is a perspective view illustrating a tray, a bonding layer, and an LED chip according to another embodiment of the present specification.

[0024] Figure 7 It is shown that Figure 6 A three-dimensional image of the tray and bonding layer after LED chip transfer.

[0025] Figure 8 is a perspective view illustrating a tray, a bonding layer, and an LED chip according to another embodiment of the present specification.

[0026] Figure 9 It is along Figure 8 Cross-sectional view along line AA'.

[0027] Figure 10 is to show that ultraviolet light is irradiated to Figure 9 A cross-sectional view of the bonding layer.

[0028] Figure 11 It shows that when Figure 10 Schematic diagram of the adhesive layer being peeled off from the tray when irradiated with ultraviolet light.

[0029] Figure 12 is a perspective view of a display device according to another embodiment of the present disclosure.

[0030] Figure 13 It shows that according to Figure 12 A cross-sectional view of a display device in a folded state.

[0031] Figure 14 It is along Figure 12 Cross-sectional view along line BB'.

[0032] Figure 15 is based on Figure 14 A cross-sectional view of a display panel.

[0033] Figure 16 yes Figure 14 Enlarged cross-sectional view of the middle region Q1.

[0034] Figure 17 is to show that ultraviolet light is irradiated to Figure 16A cross-sectional view of a case of a display device.

[0035] Figure 18 It shows that when Figure 17 Schematic diagram of the second bonding layer being peeled off from the polarizing layer when irradiated with ultraviolet light.

[0036] Figure 19 is a cross-sectional view of a display device according to another embodiment of the present disclosure.

[0037] Figure 20 yes Figure 19 Enlarged cross-sectional view of the middle region Q2.

[0038] Figure 21 is to show that ultraviolet rays are irradiated to Figure 20 A cross-sectional view of a case of a display device.

[0039] Figure 22 It shows that when Figure 21 Schematic diagram of the third bonding layer being peeled off from the cover layer when irradiated with ultraviolet light.

[0040] Figure 23 is a cross-sectional view of a display device according to yet another embodiment of the present disclosure.

[0041] Figure 24 yes Figure 23 Enlarged cross-sectional view of the middle region Q3.

[0042] Figure 25 is to show that ultraviolet rays are irradiated to Figure 24 A cross-sectional view of a case of a display device. DETAILED DESCRIPTION

[0043] Hereinafter, embodiments will be described with reference to the accompanying drawings. In the specification, when a first component (or region, layer, portion, etc.) is described as being "on," "connected," or "coupled" to a second component, it means that the first component can be directly connected / coupled to the second component or a third component can be provided therebetween.

[0044] The same reference numerals denote the same components. In addition, in the drawings, the thickness, proportion and size of the components are exaggerated in order to effectively describe the technical content. The term "and / or" includes all or more combinations that can be defined by the associated configurations.

[0045] Terms such as first and second may be used to describe various components, but the components are not limited by these terms. These terms are used only for the purpose of distinguishing one component from another. For example, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component without departing from the scope of the embodiments. The singular includes the plural unless the context clearly dictates otherwise.

[0046] Terms such as "below", "on the lower side", "above", and "on the upper side" are used to describe the relationship between components illustrated in the drawings. These terms are relative concepts and are described with respect to directions marked in the drawings.

[0047] It should be understood that terms such as “include” or “have” are intended to specify the presence of the described features, quantities, steps, operations, components, parts, or combinations thereof in the specification, and do not preclude the presence or possibility of adding one or more other features, quantities, steps, operations, components, parts, or combinations thereof.

[0048] Embodiments of this specification may include a base substrate and a bonding layer attached to the base substrate. Although the base substrate may include a substrate, a film, a tray, an insulating layer, a metal layer, etc. to which the bonding layer is attached, the embodiments of this specification are not limited thereto. The following embodiments illustrate specific base substrates and bonding layers on the base substrate in various products.

[0049] Figure 1 is a cross-sectional view illustrating a substrate, a bonding layer, and a film according to one embodiment of the present specification. Figure 2 is shown to ensure that the Figure 1 A cross-sectional view of a seed space peeled off at an edge portion between a substrate and a bonding layer. Figure 1 and Figure 2 A case where the base substrate includes a substrate SUB is shown.

[0050] Reference Figure 1 and Figure 2 , the substrate SUB according to one embodiment may be bonded to the film ADH through the bonding layer BP. Figure 1 and Figure 2 , a substrate SUB is shown as a base substrate, but the embodiments of this specification are not limited thereto. Although the substrate SUB may include a plastic substrate or a glass substrate, the embodiments of this specification are not limited thereto. For example, the plastic substrate may be a plastic substrate made of one of polyimide, polyethersulfone, polyethylene terephthalate, and polycarbonate, but the embodiments of this specification are not limited thereto. For example, the glass substrate may include glass, quartz, etc., but the embodiments of this specification are not limited thereto.

[0051] although Figure 1 and Figure 2 The film ADH provided on the bonding layer BP is shown, but any member other than the film ADH may be provided.

[0052] The bonding layer BP may bond the substrate SUB and the film ADH. The bonding layer BP may include a transparent adhesive. For example, although the transparent adhesive may be a transparent resin (OCR) or a transparent adhesive (OCA), the embodiments of the present specification are not limited thereto.

[0053] The bonding layer BP is attached to the upper surface of the substrate SUB, and when the bonding layer BP is improperly attached during the process of attaching the bonding layer BP to the upper surface of the substrate SUB, it is necessary to peel the bonding layer BP from the substrate SUB. This specification exemplifies the case where the bonding layer BP is peeled from the substrate SUB when the bonding layer BP is improperly attached during the process of attaching the bonding layer BP to the upper surface of the substrate SUB, but the bonding layer BP may be peeled from the substrate SUB in various cases.

[0054] In order to peel the bonding layer BP from the upper surface of the substrate SUB, as shown in FIG. Figure 1 As shown, it may be necessary to form a peeling space between the bonding layer BP and the substrate SUB. Figure 1 A peeling space formed at an edge portion between the bonding layer BP and the substrate SUB through a scribing process is illustrated, but embodiments of the present disclosure are not limited thereto.

[0055] like Figure 2 As shown, a peeling space SR may be formed at an edge portion between the bonding layer BP and the substrate SUB. In the peeling space SR, the bonding layer BP and the substrate SUB may be spaced apart from each other by a predetermined distance.

[0056] the following Figures 3 to 5 Shows the Figure 2 Examples of peeling the bonding layer BP from the substrate SUB by various methods.

[0057] Figure 3 It is shown that by heating Figure 2 Schematic diagram of the bonding layer being peeled off from the substrate.

[0058] Reference Figure 3 , the bonding layer BP' can be peeled off from the substrate SUB by heating with heat. Figure 2 ) and the film ADH may be located in a high-temperature oven CH. The lower plate of the rework plate RP may be attached below the substrate SUB. The upper plate of the rework plate RP may be attached above the film ADH. The ends of the lower plate and the upper plate of the rework plate RP may be connected. Although the high-temperature oven CH may be about 80° C. or above, the embodiments of the present specification are not limited thereto. The bonding layer BP (see Figure 2 ) may have reduced adhesive strength above about 80°C. When the adhesive strength of the bonding layer BP is reduced (see Figure 3When the bonding layer BP' is removed from the substrate SUB as the upper plate of the rework plate RP moves upward, the bonding layer BP' can be peeled off from the substrate SUB. Although the adhesive strength of the bonding layer BP' is reduced in a high temperature environment, it may be necessary to Figure 2 The peeling space SR is used to peel the bonding layer BP' with reduced adhesive strength from the substrate SUB.

[0059] Figure 4 It is shown that the UV reaction will be based on Figure 2 Schematic diagram of the bonding layer being peeled off from the substrate.

[0060] Reference Figure 4 , the bonding layer BP'_1 can be peeled off from the substrate SUB through ultraviolet reaction. Figure 2 The bonding layer BP can be a UV reactive adhesive. At about 365nm and 2000mJ / cm 2 Under ultraviolet wavelength conditions, the bonding layer BP may have an adhesive strength that decreases according to the ultraviolet irradiation time. For example, it can be confirmed that the adhesive strength of the bonding layer BP to the substrate SUB is about 1000 gf / inch, and the adhesive strength gradually decreases until it has an adhesive strength of about 200 gf / inch after an irradiation time of 1 hour.

[0061] When the adhesive strength of the bonding layer BP decreases (see Figure 4 Although the bonding strength of the bonding layer BP'1 is reduced by the ultraviolet reaction, it may be necessary to Figure 2 The bonding layer BP'_1 with reduced adhesive strength is peeled off from the substrate SUB by using the peeling space SR.

[0062] Figure 5 It is shown that the aqueous solution method will be based on Figure 2 Schematic diagram of the bonding layer being peeled off from the substrate.

[0063] Reference Figure 5 , the bonding layer BP can be peeled off from the substrate SUB by an aqueous method that allows water to penetrate into the interface between the bonding layer BP and the substrate SUB. When the surface of the object to which the bonding layer BP is attached is hydrophilic, the aqueous method can be used for peeling. For example, when the substrate SUB is made of a glass material, the surface of the glass is hydrophilic, and thus the bonding layer BP can be peeled off from the substrate SUB by an aqueous method. Even in this case, a peeling space SR that allows water to penetrate into the interface between the bonding layer BP and the substrate SUB may be required. As another example, when a substrate SUB made of a plastic material is applied as a base substrate, since plastic is hydrophobic, the bonding layer BP cannot be peeled off from the substrate SUB by an aqueous method.

[0064] like Figures 3 to 5As described above, in each of the heating method, the ultraviolet reaction method, and the aqueous solution method, it may be necessary to ensure a peeling space SR between the bonding layer BP and the substrate SUB (see Figure 2 When the peeling space SR is formed by the scribing process, scratches may be generated on the surface of the substrate SUB. Therefore, even when the bonding layer BP is peeled off from the substrate SUB, it may be difficult to reuse the substrate SUB.

[0065] Figure 6 is a perspective view illustrating a tray, a bonding layer, and an LED chip according to another embodiment of the present specification. Figure 7 It is shown that Figure 6 A three-dimensional image of the tray and bonding layer after LED chip transfer. Figure 6 and Figure 7 A case where the base substrate is applied to the tray TRAY is shown, but embodiments of the present specification are not limited thereto.

[0066] Reference Figure 6 and Figure 7 A bonding layer BP_1 may be provided on a tray TRAY. A plurality of LED chips LED are attached to the bonding layer BP_1. The plurality of LED chips LED may be attached to the bonding layer BP_1 on the tray TRAY and transferred or printed to each pixel of the display device. Figure 7 The plurality of LED chips LED are transferred from the bonding layer BP_1 to each pixel of the display device so that only the bonding layer BP_1 remains on the tray TRAY. Although the LED chips LED may be micro LEDs or mini LEDs, embodiments of the present specification are not limited thereto.

[0067] In order to transfer or print other LED chips, LEDs need to be removed from the tray. Figure 7 If the bonding layer BP_1 is attached, another bonding layer BP_1 needs to be attached to the tray TRAY, and it may be difficult to remove the bonding layer BP_1. In order to remove the bonding layer BP_1, the bonding layer BP_1 may be removed by applying the method according to Figures 3 to 5 However, even in this case, it is necessary to ensure the peeling space SR between the bonding layer BP_1 and the tray TRAY (see Figure 2 ), and when the peeling space SR is formed by the scribing process, scratches may be generated on the surface of the tray TRAY. Therefore, even when the bonding layer BP_1 is peeled off from the tray TRAY, it may be difficult to reuse the scratched tray TRAY.

[0068] Below, we will describe Figure 1 Substrate SUB or Figure 6 The bonding layers BP and BP_1 on the tray TRAY are removed by a peeling method that does not cause physical damage to the substrate SUB or the tray TRAY.

[0069] Figure 8 is a perspective view illustrating a tray, a bonding layer, and an LED chip according to another embodiment of the present specification. Figure 9 It is along Figure 8 Cross-sectional view along line AA'. Figure 10 is to show that ultraviolet rays are irradiated to Figure 9 A cross-sectional view of the bonding layer. Figure 11 It shows that when Figure 10 Schematic diagram of the adhesive layer being peeled off from the tray when irradiated with ultraviolet light.

[0070] Reference Figures 9 to 11 The bonding layer BP_2 may include a base film BF, a nitrogen-reactive bonding layer BPP between the base film BF and the tray TRAY, and a main bonding layer BPN on the base film BF. Although the thickness (t1+t2+t3) of the bonding layer BP_2 may range from about 350 μm to about 500 μm, embodiments of the present specification are not limited thereto.

[0071] Although the base film BF can be made of polyimide (PI), (poly) norbornene, high heat-resistant polyethylene terephthalate (PET), epoxy resin, urethane, etc., the embodiments of this specification are not limited thereto. As another example, although the base film BF can be made of a copolymer, the embodiments of this specification are not limited thereto. For example, although the base film BF can be made of a copolymer combining polymethyl methacrylate (PMMA) and a special PMMA, a copolymer combining polycarbonate (PC) and PI, a copolymer combining PMMA and PI, or a copolymer combining urethane, the embodiments of this specification are not limited thereto. Although the thickness t1 of the base film BF can range from about 50 μm to about 200 μm, the embodiments of this specification are not limited thereto.

[0072] Although the primary bonding layer BPN and the nitrogen-reactive bonding layer BPP may each include a transparent adhesive, embodiments of the present specification are not limited thereto. For example, although the transparent adhesive may be a transparent resin (OCR) or a transparent adhesive (OCA), embodiments of the present specification are not limited thereto. Although the thickness t2 of the primary bonding layer BPN may range from approximately 50 μm to approximately 150 μm, embodiments of the present specification are not limited thereto. Although the thickness t3 of the nitrogen-reactive bonding layer BPP may range from approximately 50 μm to approximately 150 μm, embodiments of the present specification are not limited thereto.

[0073] Although the main bonding layer BPN and the nitrogen-reactive bonding layer BPP may each include a silicon-based adhesive or an acryl-based adhesive, embodiments of the present disclosure are not limited thereto.

[0074] The nitrogen-reactive bonding layer (BPP) may have bonds between nitrogen atoms. For example, the nitrogen-reactive bonding layer (BPP) may include at least one of an azo compound, a diazo compound, and a pyrrole and imidazole compound. Chemical Formula 1 below represents an azo compound, Chemical Formula 2 represents a diazo compound, and Chemical Formulas 3 to 6 represent pyrrole and imidazole compounds. In Chemical Formulas 3 to 6, R may be an alkyl group.

[0075] [Chemical Formula 1]

[0076] RN=NR

[0077] (In Chemical Formula 1, R is an alkyl group)

[0078] [Chemical Formula 2]

[0079]

[0080] [Chemical Formula 3]

[0081]

[0082] [Chemical Formula 4]

[0083]

[0084] [Chemical Formula 5]

[0085]

[0086] [Chemical Formula 6]

[0087]

[0088] The nitrogen-reactive bonding layer BPP according to an embodiment of the present specification is not limited to an azo compound, a diazo compound, or a pyrroloimidazole compound.

[0089] When the nitrogen-reactive bonding layer (BPP) includes an azo compound or a diazo compound, each azo compound or diazo compound in the nitrogen-reactive bonding layer (BPP) may have a weight ratio of approximately 2 wt% or less, but embodiments of the present disclosure are not limited thereto. For example, the azo compound or diazo compound may have a weight ratio of approximately 2 wt% or less relative to the total weight of the nitrogen-reactive bonding layer (BPP). When the nitrogen-reactive bonding layer (BPP) includes a pyrroloimidazole compound, the pyrroloimidazole compound in the nitrogen-reactive bonding layer (BPP) may have a weight ratio of approximately 5 wt% or less, but embodiments of the present disclosure are not limited thereto. For example, the pyrroloimidazole compound may have a weight ratio of approximately 5 wt% or less relative to the total weight of the nitrogen-reactive bonding layer (BPP).

[0090] The content of nitrogen atoms (N) in the nitrogen-reactive bonding layer BPP may be greater than the content of nitrogen atoms (N) in the main bonding layer BPN.

[0091] The nitrogen reactive bonding layer BPP may be an ultraviolet reactive bonding layer. For example, the nitrogen reactive bonding layer BPP may react at about 320 nm to about 400 nm to generate nitrogen gas GAS. Although the ultraviolet irradiation conditions may be a wavelength range of about 320 nm to about 400 nm and a power of about 430 mW / cm2 from a ray irradiator (lamp), the nitrogen reactive bonding layer BPP may react at about 320 nm to about 400 nm to generate nitrogen gas GAS. 2 The energy density under the output condition is less than about 5000mJ / cm 2 , but the embodiments of this specification are not limited thereto.

[0092] The bonding strength between the nitrogen reactive bonding layer BPP and the tray TRAY may range from about 0.5 kgf / inch to about 2.5 kgf / inch.

[0093] like Figure 10 As shown, when the nitrogen-reactive bonding layer BPP is irradiated with ultraviolet light under the aforementioned irradiation conditions, the nitrogen-reactive bonding layer BPP' of the bonding layer BP_2' can react with the ultraviolet light. The nitrogen-reactive bonding layer BPP' can generate nitrogen gas from an azo compound, a diazo compound, or a pyrroloimidazole compound. For example, the compounds according to Chemical Formulas 1 to 6 can be converted into compounds according to Chemical Formulas 7 to 12, respectively.

[0094] [Chemical Formula 7]

[0095] 2R·+N2

[0096] (In Chemical Formula 7, R is an alkyl group)

[0097] [Chemical Formula 8]

[0098]

[0099] [Chemical Formula 9]

[0100]

[0101] [Chemical Formula 10]

[0102]

[0103] [Chemical Formula 11]

[0104]

[0105] [Chemical Formula 12]

[0106]

[0107] (In Chemical Formula 12, R is an alkyl group)

[0108] The nitrogen-reactive bonding layer BPP' can react with ultraviolet light to generate nitrogen gas GAS. The generated nitrogen gas GAS can be located between the nitrogen-reactive bonding layer BPP' and the tray TRAY. Since the nitrogen gas GAS is located between the nitrogen-reactive bonding layer BPP' and the tray TRAY, the nitrogen-reactive bonding layer BPP' can be separated from the tray TRAY by a predetermined distance, or a separation space can be formed.

[0109] although Figure 10 The adhesive strength between the nitrogen reactive bonding layer BPP′ and the tray TRAY may be less than about 0.3 kgf / inch, but the embodiments of the present specification are not limited thereto.

[0110] like Figure 11 As shown, since the nitrogen-reactive bonding layer BPP' is separated from the tray TRAY by a predetermined distance due to the nitrogen gas GAS between the nitrogen-reactive bonding layer BPP' and the tray TRAY to reduce the bonding strength between the nitrogen-reactive bonding layer BPP' and the tray TRAY, the nitrogen-reactive bonding layer BPP' can be easily peeled off from the tray TRAY. In addition, the nitrogen gas GAS generated from the nitrogen-reactive bonding layer BPP' can form a peeling space between the nitrogen-reactive bonding layer BPP' and the tray TRAY. Therefore, according to one embodiment, it is not necessary to Figure 1 and Figure 2 Therefore, since no physical damage to the tray TRAY occurs, the tray TRAY can be reused.

[0111] Figure 12 is a perspective view of a display device according to another embodiment of the present disclosure. Figure 13 It shows that according to Figure 12 A cross-sectional view of a display device in a folded state.

[0112] Reference Figure 12 and Figure 13 , the display device 10 according to one embodiment may be a foldable display device. Figure 12 is a view showing an unfolded state of the display device.

[0113] The display device 10 may include a folding area FA and an expansion area adjacent to the folding area FA. The folding area FA may extend in a first direction DR1 of the display device 10. The expansion area may include one or more expansion areas. For example, the expansion area may include a first expansion area NFA1 and a second expansion area NFA2. The first expansion area NFA1 may be located on one side of the folding area FA in the second direction DR2. The second expansion area NFA2 may be located on the other side of the folding area FA in the second direction DR2. For example, the other side in the second direction DR2 may be different from the one side in the second direction DR2. For example, the other side in the second direction DR2 may be opposite to the one side in the second direction DR2. The display device 10 may include a display area including a plurality of pixels and a non-display area outside the display area. Although the display area may include portions of the folding area FA and the expansion areas NFA1 and NFA2, and the non-display area may include other portions of the folding area FA and the expansion areas NFA1 and NFA2 that are not included in the display area, embodiments of the present disclosure are not limited thereto.

[0114] Reference Figure 13 The display device 10 may be folded based on the folding area FA. For example, when the display device 10 is folded, the first expansion area NFA1 and the second expansion area NFA2 may be disposed to overlap each other in the thickness direction.

[0115] However, the present specification is not limited thereto, and the display device 10 may be a stretchable display device or a bendable display device. In the present specification, a stretchable display device may be referred to as a display device that can display an image even when bent or stretched. Foldable display devices and stretchable display devices may have higher flexibility than general display devices. The shape of the stretchable display device may be freely changed according to the user's manipulation, such as by bending or stretching the stretchable display device. For example, when the user holds and pulls the end of the stretchable display device, the stretchable display device may be stretched by the user's force. Alternatively, when the user arranges the stretchable display device on an uneven wall, the stretchable display device may be configured to bend along the shape of the surface of the wall. In addition, when the force applied by the user is removed, the stretchable display device may return to its original shape.

[0116] Figure 14 It is along Figure 12 Cross-sectional view along line BB'.

[0117] Reference Figure 14 , the display device 10 according to one embodiment of the present specification may include a lower structure and an upper structure on the lower structure.

[0118] The lower structure may include a display panel 100, a polarizing layer 200, a backplane layer 600, a first plate layer 800, and a second plate layer 900. Although the display panel 100, the polarizing layer 200, the backplane layer 600, the first plate layer 800, and the second plate layer 900 may be represented by members, embodiments of the present specification are not limited thereto.

[0119] The display panel 100 may include a plurality of pixels provided in a display area of ​​a base substrate and a driving unit provided in a non-display area around the display area to drive the pixels.

[0120] The pixel may include a transistor connected to a driving unit through a control signal line, and a light emitting element connected to the transistor.

[0121] The transistor can be turned on or off according to a control signal applied through a control signal line to control the amount of current applied to the light emitting element.

[0122] The light-emitting element can emit light at a brightness corresponding to the amount of current applied by the transistor. Although the light-emitting element may include an organic light-emitting diode, embodiments of the present disclosure are not limited thereto. For example, the light-emitting element may include an inorganic light-emitting diode, a quantum dot diode, a micro-LED diode, or a mini-LED diode.

[0123] The base substrate may include a flexible substrate. For example, the base substrate may be an insulating plastic substrate selected from one of polyimide, polyethersulfone, polyethylene terephthalate, and polycarbonate, but the embodiments of this specification are not limited thereto. Since the base substrate of the display panel 100 includes a flexible substrate, the display device 10 may be implemented as a foldable, stretchable, or bendable display device, but the embodiments of this specification are not limited thereto.

[0124] The backplane layer 600 may be disposed below the display panel 100. The backplane layer 600 may be disposed below the display panel 100 to support the display panel 100. The backplane layer 600 may include a material capable of supporting the display panel 100. For example, although the backplane layer 600 may include polyethylene terephthalate (PET), polyimide (PI), or polycarbonate (PC), the embodiments of the present specification are not limited thereto. The backplane layer 600 may continuously maintain the curvature of the display panel 100 when the display device 10 is folded and suppress wrinkles from being generated on the upper surface of the display panel 100.

[0125] The polarizing layer 200 may be disposed above the display panel 100. The polarizing layer 200 may polarize light emitted from the display panel 100 at a polarization angle. The polarizing layer 200 may emit the light polarized at the polarization angle to the outside. The polarizing layer 200 may include a function of blocking reflection of light other than the light polarized at the polarization angle in the external light.

[0126] The plate layers 800 and 900 may be disposed below the back plate layer 600. The plate layers 800 and 900 may include a first plate layer 800 and a second plate layer 900 disposed below the first plate layer 800. The first plate layer 800 and the second plate layer 900 may comprise metal. For example, although the first plate layer 800 and the second plate layer 900 may comprise stainless steel, the embodiments of the present specification are not limited thereto. The second plate layer 900 may include a pattern SLP disposed in the folding area FA. The first plate layer 800 may be disposed on the second plate layer 900 to prevent the pattern SLP from being visible. For example, the pattern SLP may be disposed to correspond to the folding area FA. The pattern SLP may improve the folding performance of the display device by enabling the second plate layer 900 in the folding area to be easily folded and easily restored to its original state after folding. For example, the patterns SLP may be disposed to be spaced apart from each other at regular intervals. Although the pattern SLP may be an open pattern, the embodiments of the present specification are not limited thereto.

[0127] The polarization layer 200 may include a first phase retardation layer, a second phase retardation layer disposed on the first phase retardation layer, and a polarization layer disposed on the second phase retardation layer. Figure 14 , although an example in which the polarizing layer 200 and the display panel 100 are separated from each other is illustrated, embodiments of the present specification are not limited thereto, and the polarizing layer 200 may be included in the display panel 100 .

[0128] The lower structure may further include bonding layers for bonding adjacent members 100 , 200 , 600 , 800 , and 900 . The bonding layers may include a first bonding layer 710 , a second bonding layer 720 , a fourth bonding layer 740 , a fifth bonding layer 750 , and a sixth bonding layer 760 .

[0129] The first bonding layer 710 may be disposed between the display panel 100 and the polarizing layer 200. The first bonding layer 710 may connect or combine the display panel 100 and the polarizing layer 200.

[0130] The second bonding layer 720 may be disposed between the polarizing layer 200 and the cover layer 300. The second bonding layer 720 may connect or combine the polarizing layer 200 and the cover layer 300.

[0131] The fourth bonding layer 740 may be disposed between the backplane layer 600 and the display panel 100. The fourth bonding layer 740 may connect or combine the backplane layer 600 and the display panel 100.

[0132] The fifth bonding layer 750 may be disposed between the back plate layer 600 and the first plate layer 800. The fourth bonding layer 740 may connect or combine the back plate layer 600 and the first plate layer 800.

[0133] The sixth bonding layer 760 may be disposed between the first board layer 800 and the second board layer 900. The sixth bonding layer 760 may connect or combine the first board layer 800 and the second board layer 900.

[0134] Although the first bonding layer 710, the second bonding layer 720, the fourth bonding layer 740, the fifth bonding layer 750, and the sixth bonding layer 760 may each include a transparent adhesive, embodiments of the present specification are not limited thereto. For example, although the transparent adhesive may be a transparent resin (OCR) or a transparent adhesive (OCA), embodiments of the present specification are not limited thereto.

[0135] The upper structure may include a cover layer 300 .

[0136] The cover layer 300 may be disposed on the polarizing layer 200. Although the cover layer 300 may be made of a glass material including glass or quartz, the embodiments of the present specification are not limited thereto. The cover layer 300 may be disposed on the display panel 100 to protect components (e.g., a lower structure) disposed below the cover layer 300 from external influences. Although the cover layer 300 may be a cover layer formed by chemical strengthening, the embodiments of the present specification are not limited thereto. Although the cover layer 300 may be a cover window, a window cover, or a cover member, the embodiments of the present specification are not limited thereto.

[0137] The cover layer 300 protects components disposed below the cover layer 300 from external influences. However, as described above, since the cover layer 300 is made of a glass material, it may be damaged by external forces, resulting in the generation of glass fragments. These glass fragments may fly outside the display device 10. According to an embodiment of the present disclosure, to prevent the glass fragments from shattering due to damage to the cover layer 300 or to increase the durability of the cover layer 300, the display device 10 may further include at least one additional layer on the cover layer 300. For example, the upper structure of the display device 10 may further include a nitrogen-reactive bonding layer (BPP) and a film layer 400.

[0138] The film layer 400 can protect the cover layer 300. Although the film layer 400 can be a thin film sheet made of a polymer organic material, the embodiments of this specification are not limited thereto. For example, although the film layer 400 can be made of PI, (poly) norbornene, high heat-resistant PET, epoxy resin, urethane, etc., the embodiments of this specification are not limited thereto. As another example, the film layer 400 can be made of a copolymer. For example, although the film layer 400 can be made of a copolymer combining polymethyl methacrylate (PMMA) and special PMMA, a copolymer combining polycarbonate (PC) and PI, a copolymer combining PMMA and PI, or a copolymer combining urethane, the embodiments of this specification are not limited thereto. The coating layer 500 can be disposed above the film layer 400.

[0139] According to an embodiment of the present specification, although the display device may further include a coating layer implemented as a surface protection layer on the film layer 400 , the embodiment of the present specification is not limited thereto.

[0140] The nitrogen-reactive bonding layer (BPP) may include a transparent adhesive. For example, the transparent adhesive may be a transparent resin (OCR) or a transparent adhesive (OCA), but the embodiments of the present specification are not limited thereto. The nitrogen-reactive bonding layer (BPP) may be disposed between the cover layer 300 and the film layer 400. The nitrogen-reactive bonding layer (BPP) may bond or connect the cover layer 300 to the film layer 400.

[0141] Figure 15 is based on Figure 14 A cross-sectional view of a display panel.

[0142] Reference Figure 15 The display panel 100 may include a substrate 101 , a first thin film transistor 120 , a second thin film transistor 130 , a light emitting portion 150 , an encapsulation portion 170 and a touch portion 180 .

[0143] The substrate 101 may include one or more plastic materials. For example, although the substrate 101 may be a multi-substrate including multiple plastic materials (eg, polyimide), the embodiments of the present specification are not limited thereto.

[0144] The buffer layer 102 may be provided on the substrate 101. The buffer layer 102 may minimize or delay the diffusion of moisture or oxygen penetrating the substrate 101. Although the buffer layer 102 may be provided by alternately stacking silicon nitride (SiN x ) and silicon oxide (SiO x ) at least once to form the buffer layer 102, but the embodiments of this specification are not limited thereto.

[0145] The first light blocking layer 126 may be provided on the buffer layer 102. The first light blocking layer 126 may prevent light from being transmitted through the first semiconductor layer 123 of the first thin film transistor 120. For example, the first semiconductor layer 123 may be provided to overlap with the first light blocking layer 126. Although the first light blocking layer 126 may be formed of a single layer or multiple layers made of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), nickel (Ni), neodymium (Nd), and copper (Cu), or alloys thereof, the embodiments of the present specification are not limited thereto.

[0146] The first insulating layer 103 may be provided on the first light blocking layer 126. The first insulating layer 103 may prevent a short circuit between the components of the first thin film transistor 120 and the first light blocking layer 126. Although the first insulating layer 103 may be made of the same material as the buffer layer 102, the embodiments of the present specification are not limited thereto. For example, although the first insulating layer 103 may be made of an inorganic material (e.g., silicon nitride (SiNx ) or silicon oxide (SiO x )), but the embodiments of this specification are not limited to this.

[0147] The first thin film transistor 120 may be provided on the first insulating layer 103 . The first thin film transistor 120 may include a first source electrode 121 , a first gate electrode 122 , a first semiconductor layer 123 , and a first drain electrode 124 .

[0148] The first semiconductor layer 123 may be disposed on the first insulating layer 103. Although the first semiconductor layer 123 may include a metal oxide semiconductor (e.g., indium gallium zinc oxide (IGZO)) and a silicon-based semiconductor material (e.g., amorphous silicon or polycrystalline silicon), the embodiments of the present specification are not limited thereto. The first semiconductor layer 123 may include a channel region, a source region, and a drain region.

[0149] Since a polycrystalline semiconductor layer has higher mobility than an amorphous semiconductor layer and an oxide semiconductor layer, it can have low power consumption and excellent reliability. Therefore, the driving transistor can be formed of a polycrystalline semiconductor layer.

[0150] The second insulating layer 104 may be disposed on the first semiconductor layer 123. The second insulating layer 104 may be made of the same material as the first insulating layer 103 and may prevent a short circuit between the first semiconductor layer 123 and another component of the first thin film transistor 120.

[0151] The first gate 122 may be provided on the second insulating layer 104. The first gate 122 may be provided on the second insulating layer 104 to overlap with the channel region of the first semiconductor layer 123. Although the first gate 122 may be formed of a single layer or multiple layers made of molybdenum (Mo), copper (Cu), titanium (Ti), aluminum (Al), chromium (Cr), gold (Au), nickel (Ni), neodymium (Nd), or compounds thereof, the embodiments of the present specification are not limited thereto. The first gate 122 may be provided together with a gate line.

[0152] The third insulating layer 105 may be disposed on the first gate electrode 122. Although the third insulating layer 105 may be made of the same material as the first insulating layer 103 or the second insulating layer 104, the embodiments of the present disclosure are not limited thereto.

[0153] The first source electrode 121 and the first drain electrode 124 may be disposed on the third insulating layer 105 .

[0154] The first source electrode 121 and the first drain electrode 124 may be electrically connected to the first semiconductor layer 123 through a contact hole. The first source electrode 121 and the first drain electrode 124 may be made of a metal material. For example, the first source electrode 121 and the first drain electrode 124 may be formed of a single layer or multiple layers made of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or alloys thereof, but the embodiments of the present specification are not limited thereto.

[0155] The first source electrode 121 and the first drain electrode 124 may be provided together with the data line. For example, although the data line may be made of the same material as the first source electrode 121 and the first drain electrode 124 and formed coplanar therewith, the embodiments of the present disclosure are not limited thereto.

[0156] The storage electrode 140 may be disposed to be spaced apart from the first thin film transistor 120. The storage electrode 140 may include a first storage electrode 141, a second storage electrode 142, and a third storage electrode 143.

[0157] Although the first storage electrode 141 may be made of the same material as the first gate electrode 122 and may be formed coplanar therewith, embodiments of the present disclosure are not limited thereto.

[0158] The second storage electrode 142 may be disposed on the first storage electrode 141. The second storage electrode 142 may be disposed on the third insulating layer 105, and the third insulating layer 105 between the first storage electrode 141 and the second storage electrode 142 may function as a dielectric to generate capacitance. Although the second storage electrode 142 may be made of the same material as the first storage electrode 141, embodiments of the present specification are not limited thereto.

[0159] The second thin film transistor 130 may be disposed to be spaced apart from the first thin film transistor 120 and the storage electrode 140. The second thin film transistor 130 may include a second source electrode 131, a second gate electrode 132, a second semiconductor layer 133, and a second drain electrode 134.

[0160] The second light blocking layer 136 may be disposed coplanar with the second storage electrode 142 .

[0161] Similar to the first light blocking layer 126, the second light blocking layer 136 can prevent light from being directed to the second semiconductor layer 133, thereby extending the life of the second thin film transistor 130. For example, the second semiconductor layer 133 can be disposed to overlap with the second light blocking layer 136.

[0162] The fourth insulating layer 106 may be disposed on the second light blocking layer 136. Although the fourth insulating layer 106 may be made of the same material as the first insulating layer 103, the second insulating layer 104, or the third insulating layer 105, the embodiments of the present disclosure are not limited thereto.

[0163] The second semiconductor layer 133 may be disposed on the fourth insulating layer 106. The second semiconductor layer 133 may include a source region, a drain region, and a channel region between the source region and the drain region.

[0164] Although the second semiconductor layer 133 may include a metal oxide semiconductor (eg, indium gallium zinc oxide (IGZO)) and a silicon-based semiconductor material (eg, amorphous silicon or polycrystalline silicon), embodiments of the present disclosure are not limited thereto.

[0165] The fifth insulating layer 108 may be disposed on the second semiconductor layer 133. Although the fifth insulating layer 108 may be made of the same material as the first insulating layer 103, the second insulating layer 104, the third insulating layer 105, or the fourth insulating layer 106, the embodiments of the present disclosure are not limited thereto.

[0166] The second gate 132 may be disposed on the fifth insulating layer 108 .

[0167] The second gate 132 may be made of the same material as the first gate 122. For example, although the second gate 132 may be formed of a single layer or multiple layers made of molybdenum (Mo), copper (Cu), titanium (Ti), aluminum (Al), chromium (Cr), gold (Au), nickel (Ni), neodymium (Nd), or a compound thereof, the embodiments of the present specification are not limited thereto.

[0168] The sixth insulating layer 109 may be disposed on the second gate 132. Although the sixth insulating layer 109 may be made of the same material as the first insulating layer 103, the second insulating layer 104, the third insulating layer 105, the fourth insulating layer 106, or the fifth insulating layer 108, the embodiments of the present disclosure are not limited thereto.

[0169] The first source electrode 121 , the first drain electrode 124 , the third storage electrode 143 , the second source electrode 131 , and the second drain electrode 134 may be disposed on the sixth insulating layer 109 .

[0170] Although the third storage electrode 143, the second source electrode 131, and the second drain electrode 134 may be made of the same material as the first source electrode 121 and the first drain electrode 124 and disposed coplanar therewith, embodiments of the present specification are not limited thereto. For example, although the third storage electrode 143, the second source electrode 131, and the second drain electrode 134 may be formed of a single layer or multiple layers made of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or alloys thereof, embodiments of the present specification are not limited thereto.

[0171] Although the first thin film transistor 120 may be a driving transistor and the second thin film transistor 130 may be a switching transistor, embodiments of the present disclosure are not limited thereto.

[0172] The first protection layer 111 may be disposed on the first source electrode 121 and the first drain electrode 124 .

[0173] The first protective layer 111 may planarize the upper portion of the first thin film transistor 120 and protect the first thin film transistor 120. The first protective layer 111 may be made of an organic material. For example, the first protective layer 111 may be made of an organic material including acrylic resin, epoxy resin, phenolic resin, polyamide resin, or polyimide resin, but the embodiments of the present specification are not limited thereto.

[0174] The second protective layer 112 may be disposed on the first protective layer 111. Although the second protective layer 112 may be made of the same material as the first protective layer 111, embodiments of the present disclosure are not limited thereto.

[0175] The connection electrode 145 may be disposed between the first protection layer 111 and the second protection layer 112 .

[0176] The connection electrode 145 may electrically connect the first thin film transistor 120 to the light emitting portion 150. Although the connection electrode 145 may be made of the same material as the first source electrode 121 and the first drain electrode 124, the embodiments of the present disclosure are not limited thereto.

[0177] Although the connection electrode 145 may be formed of a single layer or multiple layers made of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or alloys thereof, the embodiments of the present specification are not limited thereto.

[0178] The light emitting portion 150 may be disposed on the second protective layer 112. The light emitting portion 150 may include an anode 151, an organic layer 152, and a cathode 153.

[0179] The anode 151 may be disposed on the second protective layer 112. The anode 151 may be electrically connected to the first thin film transistor 120 through a contact hole formed in the second protective layer 112. Although the anode 151 may be a reflective electrode that reflects light, the embodiments of the present specification are not limited thereto. Although the anode 151 may include a metal material having high reflectivity (e.g., a stacked structure (Ti / Al / Ti) of aluminum (Al) and titanium (Ti), a stacked structure (ITO / Al / ITO) of aluminum (Al) and indium tin oxide (ITO), or an APC alloy), and may be formed of a single layer or multiple layers, the embodiments of the present specification are not limited thereto.

[0180] The organic layer 152 may be provided on the anode 151. The organic layer 152 may include one or more light-emitting structures (or light-emitting elements or components) stacked on the anode 151 in the order of a hole transport layer and an electron transport layer or in the reverse order. For example, although the hole transfer layer may include a hole transport layer, a hole injection layer, an electron blocking layer, a p-type charge generation layer, etc., the embodiments of this specification are not limited thereto. For example, although the electron transfer layer may include an electron transport layer, an electron injection layer, a hole blocking layer, an n-type charge generation layer, etc., the embodiments of this specification are not limited thereto. Although the organic layer 152 may be an organic light-emitting layer, an inorganic light-emitting layer, a quantum dot light-emitting layer, a micro light-emitting diode, a micro-mini light-emitting diode, etc., the embodiments of this specification are not limited thereto. For example, the organic layer 152 of the display panel 100 according to one embodiment of the present specification may include an organic light-emitting layer. The organic layer 152 may include a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer. Although the organic layer 152 may be a white light-emitting layer, the embodiments of this specification are not limited thereto.

[0181] The cathode 153 may be provided on the organic layer 152. Although the cathode 153 may be a transparent electrode that reflects light, the embodiments of the present specification are not limited thereto. For example, although the cathode 153 may include a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO), or a metal that transmits visible light, the embodiments of the present specification are not limited thereto.

[0182] The embankment 154 can be arranged to expose the anode 151. The embankment 154 can define the opening (or light-emitting area) of the sub-pixel and can be arranged to cover the edge portion of the anode 151. Each sub-pixel can include a red light-emitting area, a green light-emitting area, and a blue light-emitting area. For example, a sub-pixel can be a pixel, but is not limited by the term. Although the embankment 154 can be made of a material containing a black pigment, or an organic material such as a benzocyclobutene resin, a polyimide resin, an acrylic resin, or a photosensitive polymer, the embodiments of this specification are not limited thereto. When the embankment 154 is made of a material containing a black pigment or a black dye, it can be a black embankment. When the embankment 154 is made of a material containing a black pigment or a black dye, it can block light from the outside or light reflected from the outside, thereby further increasing the brightness of the display device. A spacer can be further arranged on the embankment 154. Although the spacer can be made of the same material as the embankment 154, the embodiments of the present disclosure are not limited thereto.

[0183] The encapsulation portion 170 may be disposed on the embankment 154 or the light emitting portion 150. The encapsulation portion 170 may include one or more insulating layers. For example, the encapsulation portion 170 may include a first encapsulation layer 171, a second encapsulation layer 172 disposed on the first encapsulation layer 171, and a third encapsulation layer 173 disposed on the second encapsulation layer 172. The encapsulation portion 170 may include one or more inorganic layers and one or more organic layers. For example, although the first encapsulation layer 171 and the third encapsulation layer 173 may include an inorganic material and the second encapsulation layer 172 may include an organic material, the embodiments of the present specification are not limited thereto.

[0184] The buffer layer 181 may be provided on the encapsulation portion 170. For example, the buffer layer 181 may be provided on the third encapsulation layer 173. Although the buffer layer 181 may be made of the same material as the buffer layer 102, the embodiments of the present specification are not limited thereto. The insulating layer 184 may be provided on the buffer layer 181. The insulating layer 184 may prevent short circuits between the touch electrodes. Although the insulating layer 184 may be made of silicon oxide (SiO x ), silicon nitride (SiN x ) or multiple layers thereof, but the embodiments of the present specification are not limited thereto. The first touch electrode 185 may be provided on the insulating layer 184. The first touch electrode 185 may include a 1a touch electrode 185a extending in a first direction and a 1b touch electrode 185b extending in a second direction different from the first direction.

[0185] The second touch electrode 182 may be disposed between the buffer layer 181 and the insulating layer 184 .

[0186] The second touch electrode 182 may be electrically connected to the 1a touch electrode 185a through a contact hole formed in the insulating layer 184. For example, the 1a touch electrode 185a and the second touch electrode 182 may extend in the first direction.

[0187] The first touch electrodes 185 and the second touch electrodes 182 may include a metal material. For example, the first touch electrodes 185 and the second touch electrodes 182 may be made of titanium (Ti), nickel (Ni), aluminum (Al), or alloys thereof and may be formed of three layers, such as titanium (Ti) / aluminum (Al) / titanium (Ti), but the embodiments of the present specification are not limited thereto.

[0188] Figure 16 yes Figure 14 Enlarged cross-sectional view of the middle region Q1. Figure 17 is to show that ultraviolet light is irradiated to Figure 16 A cross-sectional view of a case of a display device. Figure 18 It shows that when Figure 17 Schematic diagram of the second bonding layer being peeled off from the polarizing layer when irradiated with ultraviolet light.

[0189] Reference Figures 16 to 18 Although the thickness t1 of the film layer 400 may range from about 25 μm to about 100 μm, the embodiments of the present disclosure are not limited thereto. Although the thickness t3 of the nitrogen-reactive bonding layer BPP may range from about 10 μm to about 150 μm, the embodiments of the present disclosure are not limited thereto.

[0190] Although the thickness t4 of the cover layer 300 may range from about 25 μm to about 100 μm, embodiments of the present disclosure are not limited thereto.

[0191] Although the cover layer 300 may include plastic, the embodiments of the present specification are not limited thereto.Although the cover layer 300 may be made of an organic material including acrylic resin, epoxy resin, phenolic resin, polyamide resin, or polyimide resin, the embodiments of the present specification are not limited thereto.

[0192] Although the second bonding layer 720 and the nitrogen reactive bonding layer BPP may each include a transparent adhesive, the embodiments of the present specification are not limited thereto. For example, although the transparent adhesive may be a transparent resin (OCR) or a transparent adhesive (OCA), the embodiments of the present specification are not limited thereto.

[0193] Although the main bonding layer 720 and the nitrogen-reactive bonding layer BPP may each include a silicon-based adhesive or an acryl-based adhesive, embodiments of the present specification are not limited thereto.

[0194] For example, the nitrogen-reactive bonding layer BPP may include at least one of an azo compound, a diazo compound, and a pyrroloimidazole compound.

[0195] The azo compound and the diazo compound can each have a predetermined color, and the pyrroloimidazole compound can be a transparent compound. The nitrogen-reactive bonding layer (BPP) can be located in the emission direction of the display panel 100. Therefore, the nitrogen-reactive bonding layer (BPP) should meet a transmittance requirement. Furthermore, since the nitrogen-reactive bonding layer (BPP) is located in the emission direction, it is preferable to minimize haze caused by scattering of the azo compound, diazo compound, or pyrroloimidazole compound in the nitrogen-reactive bonding layer (BPP). For example, while the transmittance requirement of the nitrogen-reactive bonding layer (BPP) can be approximately 98% or higher and the haze requirement can be approximately 1% or lower, embodiments of the present disclosure are not limited thereto.

[0196] Since the pyrroloimidazole compound is a transparent compound, the transmittance (%) of the nitrogen-reactive bonding layer BPP containing the pyrroloimidazole compound can be 100 regardless of the content (wt%) of the pyrroloimidazole compound. In addition, it was confirmed that even when the content (wt%) of the pyrroloimidazole compound in the nitrogen-reactive bonding layer BPP was 0.5 wt%, 1.0 wt%, 2.0 wt%, and 5.0 wt%, the haze (%) ranged from about 0.2% to about 0.3%.

[0197] Since azo compounds or diazo compounds are opaque compounds with color, the transmittance and haze increase in proportion to the content (wt%) of the azo compound or diazo compound. For example, it was confirmed that when the content (wt%) of the azo compound or diazo compound in the nitrogen-reactive bonding layer BPP was 0.25wt%, the transmittance (%) exceeded 99% and the haze (%) was 0.3%. For example, it was confirmed that when the content (wt%) of the azo compound or diazo compound in the nitrogen-reactive bonding layer BPP was 0.5wt%, the transmittance (%) was 98% and the haze (%) was 0.5%. For example, it was confirmed that when the content (wt%) of the azo compound or diazo compound in the nitrogen-reactive bonding layer BPP was 1wt%, the transmittance (%) was 90% and the haze (%) was 0.7%. For example, it was confirmed that when the content (wt%) of the azo compound or diazo compound in the nitrogen-reactive bonding layer BPP was 2 wt%, the transmittance (%) was 87.1% and the haze (%) was 1.2%. Therefore, in the case of the display device 10 according to the embodiment, in order to meet the transmittance condition or haze condition of the nitrogen-reactive bonding layer BPP, the content (wt%) of the azo compound or diazo compound in the nitrogen-reactive bonding layer BPP can be approximately 2 wt% or less.

[0198] The content of nitrogen atoms (N) in the nitrogen-reactive bonding layer BPP may be greater than the content of nitrogen atoms (N) in the second bonding layer 720 .

[0199] The nitrogen reactive bonding layer BPP may be an ultraviolet reactive bonding layer. For example, the nitrogen reactive bonding layer BPP may react at about 320 nm to about 400 nm to generate nitrogen gas GAS. Although the ultraviolet irradiation conditions may be a wavelength range of about 320 nm to about 400 nm and a power of about 430 mW / cm2 of the irradiator, the nitrogen reactive bonding layer BPP may react at about 320 nm to about 400 nm to generate nitrogen gas GAS. 2 The energy density under the output condition is less than about 5000mJ / cm 2 , but the embodiments of this specification are not limited thereto.

[0200] Hereinafter, the first experiment on the ultraviolet irradiation conditions of the nitrogen reactive bonding layer BPP will be described. The width of the sample of the first experiment, the material of the adhesive, or the thickness of the adhesive does not limit the content of this specification. The width of the first sample of the first experiment was formed to be 5 cm. The first sample was composed of glass, a first adhesive on the glass (with Figure 16 of the second bonding layer 720), a polymer film on an adhesive (with the same material as Figure 16 the same material as the cover layer 300), a second adhesive on the polymer film ( Figure 16 The nitrogen reactive bonding layer BPP of the same material) and the base film on the second adhesive (with Figure 14 The first adhesive is a silicon-based adhesive and is formed to have a thickness of about 10 μm. The polymer film is a polyimide and is formed to have a thickness of about 50 μm. Before ultraviolet irradiation, the bonding strength between the glass and the first adhesive was measured to be about 1.23 kgf / inch. After one ultraviolet irradiation, it can be confirmed that bubbles are generated on the entire surface of the first sample, and the bonding strength between the glass and the first adhesive is measured to be 0.41 kgf / inch, which is about 67% lower than before the ultraviolet irradiation. After the second ultraviolet irradiation, the bonding strength between the glass and the first adhesive is measured to be about 0.31 kgf / inch, and after the third ultraviolet irradiation, the bonding strength between the glass and the first adhesive is measured to be about 0.32 kgf / inch. It is confirmed that there is no significant difference between the bonding strength between the glass and the first adhesive after the second ultraviolet irradiation and the bonding strength between the glass and the first adhesive after the third ultraviolet irradiation. Therefore, as a result of the first experiment, it is confirmed that the effective number of ultraviolet irradiations for weakening the bonding strength between the glass and the first adhesive is 2, but the embodiments of this specification are not limited thereto. In addition, it was confirmed that when the first sample was irradiated with ultraviolet light, nitrogen (or bubbles) was generated from the second adhesive, thereby reducing the bonding strength between the glass and the first adhesive. In the first experiment, in order to facilitate the experiment, the first sample was replaced by glass. Figure 16Therefore, there may be a difference in the bonding strength between the glass and the first adhesive and between the polarizing layer 200 and the first adhesive before and after the ultraviolet irradiation. However, the results of the first experiment confirmed that even in the case of the display device 10 according to the second embodiment, the nitrogen-reactive bonding layer BPP was irradiated with ultraviolet rays (significantly twice) to weaken the bonding strength between the polarizing layer 200 and the second bonding layer 720.

[0201] The adhesive strength between the second bonding layer 720 and the polarizing layer 200 may be about 0.8 kgf / inch or more. For example, although the second bonding layer 720 may include an acrylic-based adhesive, embodiments of the present specification are not limited thereto.

[0202] Hereinafter, a second experiment will be described regarding the adhesive strength between glass and the first adhesive according to the material or thickness of the first adhesive of the first, second, third, and fourth samples during ultraviolet irradiation. The width of the samples of the second experiment, the material of the adhesive, or the thickness of the adhesive does not limit the contents of this specification. The width of each sample is 5 cm. The first sample consists of glass, the first adhesive on the glass (with Figure 16 of the second bonding layer 720), a polymer film on the adhesive (with Figure 16 the same material as the cover layer 300), a second adhesive on the polymer film ( Figure 16 The nitrogen reactive bonding layer BPP of the same material) and the base film on the second adhesive (with Figure 14 The first adhesive is a silicone-based adhesive and is formed to have a thickness of about 10 μm. The polymer film is a polyimide and is formed to have a thickness of about 50 μm. The second sample is different from the first sample in that the first adhesive is an acrylic-based adhesive and has a thickness of about 15 μm, and the third sample is different from the first sample in that the first adhesive is the same silicone-based adhesive as the first sample but has a thickness of about 150 μm. The fourth sample is different from the third sample in that it is an acrylic-based adhesive.

[0203] In the case of the first sample, the bond strength between the glass and the first adhesive was measured to be approximately 1.23 kgf / inch before UV irradiation. After a single UV irradiation, bubbles were confirmed to be generated across the entire surface of the first sample, and the bond strength between the glass and the first adhesive was measured to be 0.41 kgf / inch, a decrease of approximately 67% compared to before UV irradiation.

[0204] In the case of the second sample, the bond strength between the glass and the first adhesive was measured to be approximately 1.19 kgf / inch before UV irradiation. After one UV irradiation session, bubbles were confirmed to have formed across the entire surface of the first sample, and the bond strength between the glass and the first adhesive was measured to be 0.54 kgf / inch, a decrease of approximately 55% compared to before UV irradiation.

[0205] In the case of the third sample, before ultraviolet irradiation, the bonding strength between the glass and the first adhesive was measured to be approximately 3.94 kgf / inch, but after one ultraviolet irradiation, the bonding strength between the glass and the first adhesive was measured to be approximately 3.59 kgf / inch, which was a decrease of approximately 9% compared to before ultraviolet irradiation.

[0206] In the case of the fourth sample, before ultraviolet irradiation, the bonding strength between the glass and the first adhesive was measured to be approximately 2.45 kgf / inch, but after one ultraviolet irradiation, the bonding strength between the glass and the first adhesive was measured to be approximately 2.31 kgf / inch, which was a decrease of approximately 6% compared to before ultraviolet irradiation.

[0207] As a result of the second experiment, it was confirmed that when the first adhesive was a silicone-based adhesive, the adhesive strength decreased at a greater rate after ultraviolet irradiation than when the first adhesive was an acrylic-based adhesive. This is because silicone-based adhesives have a free volume fraction compared to acrylic-based adhesives. The free volume fraction can be empty space or a free volume portion. Therefore, since bubbles (or nitrogen) generated from the second adhesive can pass through the second adhesive (i.e., silicone-based adhesive) better than the first adhesive (i.e., acrylic-based adhesive), when the first adhesive was a silicone-based adhesive, the adhesive strength decreased at a greater rate after ultraviolet irradiation than when the first adhesive was an acrylic-based adhesive.

[0208] Furthermore, it was confirmed that the thinner the thickness of the first adhesive, the greater the decrease in the bond strength between the glass and the first adhesive after UV irradiation. That is, as the thickness of the first adhesive becomes thinner, the path for bubbles (or nitrogen) generated from the second adhesive (or nitrogen-reactive bonding layer) to reach the interface between the first adhesive and the glass during UV irradiation is shorter, so more bubbles (or nitrogen) can be present at the interface between the first adhesive and the glass, thereby weakening the bond strength between the first adhesive and the glass. For example, it was confirmed that when the thickness of the first adhesive ranges from about 10 μm to about 15 μm, the bond strength to the glass after UV irradiation is significantly reduced.

[0209] In the second experiment, in order to facilitate the experiment, each of the first sample, the second sample, the third sample and the fourth sample was replaced by glass. Figure 16The polarizing layer 200 is formed between the glass and the first adhesive, and between the polarizing layer 200 and the first adhesive before and after ultraviolet irradiation. The results of the second experiment confirmed that even in the display device 10 according to the second embodiment, as the thickness of the second bonding layer 720 between the polarizing layer 200 and the cover layer 300 decreases, the bonding strength between the polarizing layer 200 and the second bonding layer 720 is weakened.

[0210] like Figure 17 As shown, when the nitrogen-reactive bonding layer BPP is irradiated with ultraviolet light under the aforementioned irradiation conditions, the nitrogen-reactive bonding layer BPP' reacts with the ultraviolet light. As confirmed by the results of the first and second experiments, the nitrogen-reactive bonding layer BPP' reacts with the ultraviolet light to generate nitrogen gas GAS. For example, although ultraviolet light may be irradiated once or twice, the embodiments of this specification are not limited thereto. The generated nitrogen gas GAS may be located between the second bonding layer 720 and the polarizing layer 200. Since the nitrogen gas GAS is located between the second bonding layer 720 and the polarizing layer 200, the second bonding layer 720 may be separated from the polarizing layer 200 by a predetermined distance, or a separation space may be formed.

[0211] Figure 17 The adhesive strength between the second bonding layer 720 and the polarizing layer 200 may be less than about 0.5 kgf / inch. For example, although the second bonding layer 720 may be an acrylic adhesive and have a thickness of about 15 μm, the embodiments of the present specification are not limited thereto.

[0212] like Figure 17 and Figure 18 As shown, since the second bonding layer 720 is separated from the polarizing layer 200 by a predetermined distance through the nitrogen GAS between the second bonding layer 720 and the polarizing layer 200 to reduce the adhesive strength between the second bonding layer 720 and the polarizing layer 200, the second bonding layer 720 can be easily peeled off from the polarizing layer 200. In addition, a peeling space can be formed between the second bonding layer 720 and the polarizing layer 200 by the nitrogen GAS generated from the nitrogen reactive bonding layer BPP'. Therefore, according to another embodiment, the above description of Figure 1 and Figure 2 Therefore, since physical damage to the polarizing layer 200 does not occur, the polarizing layer 200 can be reused.

[0213] Furthermore, based on the display device 10 according to the second embodiment, as described above, in order to peel the second bonding layer 720 from the polarizing layer 200, a nitrogen-reactive bonding layer (BPP) that reacts with ultraviolet light can be applied, thereby preventing the nitrogen-reactive bonding layer (BPP) from unintentionally deforming (BPP->BPP') under the high-temperature reliability evaluation conditions of the display device 10. For example, although the display device 10 may be a display device requiring high reliability, such as a navigation display device, the embodiments of this specification are not limited thereto. For example, the high-temperature reliability evaluation conditions of the display device 10 may include a haze reliability evaluation, a yellowness index evaluation, and a single product reliability evaluation, and the single product reliability evaluation may include a single product reliability evaluation at high temperature and a single product reliability evaluation at high temperature and high humidity. During the haze reliability evaluation, the display device 10 may be exposed to an environment of approximately 105°C for 500 hours. During the yellowness index evaluation, the display device 10 may be exposed to an environment of approximately 105°C for 500 hours. During the high-temperature reliability evaluation, the display device 10 may be exposed to an environment of approximately 105°C for 500 hours. During the high-temperature and high-humidity reliability evaluation, the display device 10 may be exposed to an environment of approximately 85°C for 500 hours at an 80% transmittance. For example, if the nitrogen-reactive bonding layer (BPP) is a thermally emissive nitrogen-reactive bonding layer that generates nitrogen gas during thermal emission, the nitrogen-reactive bonding layer may unintentionally generate nitrogen gas during the high-temperature reliability evaluation of the display device 10, thereby causing defects in the display device 10. However, in the case of the display device 10 according to the second embodiment, since the nitrogen-reactive bonding layer (BPP) that reacts to ultraviolet light is used, there is an advantage in that defects in the display device 10 that may occur during the high-temperature reliability evaluation can be prevented.

[0214] Figure 19 is a cross-sectional view of a display device according to another embodiment of the present disclosure. Figure 20 yes Figure 19 Enlarged cross-sectional view of the middle region Q2. Figure 21 is to show that ultraviolet light is irradiated to Figure 20 A cross-sectional view of a case of a display device. Figure 22 It shows that when Figure 21 Schematic diagram of the third bonding layer being peeled off from the cover layer when irradiated with ultraviolet light.

[0215] Reference Figures 19 to 22 The upper structure of the display device 11 according to another embodiment may have a third bonding layer 730 disposed between the cover layer 300 and the film layer 400. The remaining components are substantially the same as those of the embodiment. Figure 14 、 Figures 16 to 18 The components described in are the same and therefore may be denoted by the same reference numerals, and their overlapping contents may be omitted or simplified.

[0216] The third bonding layer 730 may include a main bonding layer (BPN) and a nitrogen-reactive bonding layer (BPP) on the main bonding layer (BPN). Although the thickness t1 of the membrane layer 400 may range from approximately 25 μm to approximately 100 μm, embodiments of the present disclosure are not limited thereto. Although the thickness t2 of the main bonding layer (BPN) may range from approximately 10 μm to approximately 150 μm, embodiments of the present disclosure are not limited thereto. Although the thickness t3 of the nitrogen-reactive bonding layer (BPP) may range from approximately 10 μm to approximately 150 μm, embodiments of the present disclosure are not limited thereto.

[0217] Figure 9 The bonding layer BP_2 may include a main bonding layer BPN and a nitrogen reactive bonding layer BPP disposed above and below the base film BF, respectively. Figure 20 The third bonding layer 730 may have a main bonding layer BPN and a nitrogen reactive bonding layer BPP provided or stacked as a double layer.

[0218] Although the main bonding layer BPN and the nitrogen reactive bonding layer BPP may each include a transparent adhesive, embodiments of the present specification are not limited thereto. For example, although the transparent adhesive may be a transparent resin (OCR) or a transparent adhesive (OCA), embodiments of the present specification are not limited thereto.

[0219] Although the main bonding layer BPN and the nitrogen-reactive bonding layer BPP may each include a silicon-based adhesive or an acryl-based adhesive, embodiments of the present disclosure are not limited thereto.

[0220] For example, the nitrogen-reactive bonding layer BPP may include at least one of an azo compound, a diazo compound, and a pyrroloimidazole compound.

[0221] When the nitrogen-reactive bonding layer (BPP) includes an azo compound or a diazo compound, each azo compound or diazo compound in the nitrogen-reactive bonding layer (BPP) may have a weight ratio of approximately 2 wt% or less, but embodiments of the present disclosure are not limited thereto. For example, the azo compound or diazo compound may have a weight ratio of approximately 2 wt% or less relative to the total weight of the nitrogen-reactive bonding layer (BPP). When the nitrogen-reactive bonding layer (BPP) includes a pyrroloimidazole compound, the pyrroloimidazole compound in the nitrogen-reactive bonding layer (BPP) may have a weight ratio of approximately 5 wt% or less. For example, the pyrroloimidazole compound may have a weight ratio of approximately 5 wt% or less relative to the total weight of the nitrogen-reactive bonding layer (BPP).

[0222] The content of nitrogen atoms (N) in the nitrogen-reactive bonding layer BPP may be greater than the content of nitrogen atoms (N) in the main bonding layer BPN.

[0223] The nitrogen reactive bonding layer BPP may be an ultraviolet reactive bonding layer. For example, the nitrogen reactive bonding layer BPP may react at about 320 nm to about 400 nm to generate nitrogen gas GAS. Although the ultraviolet irradiation conditions may be a wavelength range of about 320 nm to about 400 nm and a power of about 430 mW / cm2 of the irradiator, the nitrogen reactive bonding layer BPP may react at about 320 nm to about 400 nm to generate nitrogen gas GAS. 2 The energy density under the output condition is less than about 5000mJ / cm 2 , but the embodiments of this specification are not limited thereto.

[0224] The adhesive strength between the main bonding layer BPN and the cover layer 300 may range from about 1 kgf / inch to about 4 kgf / inch.

[0225] The results of the first and second experiments described in the second embodiment can also be applied to the third embodiment. The results of the first experiment showed that the effective number of UV irradiation times to weaken the bond strength between the glass and the first adhesive was two, and that when the first sample was irradiated with UV light, nitrogen gas (or bubbles) was generated from the second adhesive, thereby reducing the bond strength between the glass and the first adhesive. The results of the second experiment showed that when the first adhesive was a silicone-based adhesive, the bond strength decreased at a greater rate after UV irradiation than when the first adhesive was an acrylic-based adhesive. Furthermore, as the thickness of the first adhesive decreased, the bond strength between the glass and the first adhesive after UV irradiation decreased significantly.

[0226] like Figure 21 and Figure 22 As shown, when the nitrogen-reactive bonding layer BPP is irradiated with ultraviolet light under the aforementioned irradiation conditions, the nitrogen-reactive bonding layer BPP' of the third bonding layer 730' may react with the ultraviolet light. The nitrogen-reactive bonding layer BPP' may react with the ultraviolet light to generate nitrogen gas GAS. The generated nitrogen gas GAS may be located between the main bonding layer BPN and the cover layer 300. Since the nitrogen gas GAS is located between the main bonding layer BPN and the cover layer 300, the main bonding layer BPN may be separated from the cover layer 300 by a predetermined distance, or a separation space may be formed.

[0227] The adhesive strength between the main bonding layer BPN and the cover layer 300 may be less than about 0.3 kgf / inch.

[0228] Since the main bonding layer BPN and the cover layer 300 are separated by a predetermined distance through the nitrogen gas GAS between the main bonding layer BPN and the cover layer 300 to reduce the adhesive strength between the main bonding layer BPN and the cover layer 300, the main bonding layer BPN can be easily peeled off from the cover layer 300. In addition, a peeling space can be formed between the main bonding layer BPN and the cover layer 300 by the nitrogen gas GAS generated from the nitrogen reactive bonding layer BPP'. Therefore, according to another embodiment, the above description of Figure 1 and Figure 2 Therefore, since physical damage to the cover layer 300 does not occur, the cover layer 300 can be reused.

[0229] Figure 23 is a cross-sectional view of a display device according to yet another embodiment of the present disclosure. Figure 24 yes Figure 23 Enlarged cross-sectional view of the middle region Q3. Figure 25 is to show that ultraviolet light is irradiated to Figure 24 A cross-sectional view of a case of a display device.

[0230] Reference Figures 23 to 25 According to yet another embodiment, the display device 12 may be implemented as a stretchable display device.

[0231] The display device 12 may include a panel layer 900 ′, a lower stretchable substrate 1000 , a circuit element layer CEL, a light emitting element layer EL, an upper stretchable panel TPL, a first stretchable panel CSB, a protective stretchable panel PSB, a nitrogen reactive bonding layer BPP, and a coating layer 500 .

[0232] Although the ply 900' may include Figure 14 The first board layer 800 and the second board layer 900 are made of the same material, but the embodiments of this specification are not limited thereto.

[0233] The lower stretchable substrate 1000 may be provided on the plate layer 900'. The lower stretchable substrate 1000 is a flexible substrate and may be made of a bendable or stretchable insulating material. For example, the lower stretchable substrate 1000 may be made of an elastic polymer such as silicone rubber (e.g., polydimethylsiloxane; PDMS), polyurethane (PU), or polytetrafluoroethylene (PTFE), and thus may have flexible properties. However, embodiments according to the present specification are not limited thereto.

[0234] The first bonding layer 1100 may be disposed between the plate layer 900 ′ and the lower stretchable substrate 1000 . The plate layer 900 ′ and the lower stretchable substrate 1000 may be bonded by the first bonding layer 1100 .

[0235] The circuit element layer CEL may be provided on the lower stretchable substrate 1000. The circuit element layer CEL may include Figure 15 The substrate described in the embodiment of the present invention and at least one thin film transistor can be turned on or off according to a control signal applied through a control signal line to adjust the amount of current applied to the light emitting element layer EL.

[0236] The first bonding layer 1110 may be provided between the circuit element layer CEL and the lower stretchable substrate 1000. The circuit element layer CEL and the lower stretchable substrate 1000 may be bonded by the first bonding layer 1110.

[0237] The light-emitting element layer EL may be provided on the circuit element layer CEL. The light-emitting element layer EL may include at least one light-emitting element. The light-emitting element may emit light having a brightness corresponding to the amount of current applied by the transistor. Although the light-emitting element may include an organic light-emitting diode, the embodiments of the present disclosure are not limited thereto. For example, although the light-emitting element may include an inorganic light-emitting diode, a quantum dot diode, a micro-LED diode, a mini-LED diode, etc., the embodiments of the present specification are not limited thereto.

[0238] The upper stretchable substrate TPL may be provided on the light emitting element layer EL. The upper stretchable substrate TPL is, for example, a flexible substrate and may be made of a bendable or stretchable insulating material. For example, the upper stretchable substrate TPL may be made of an elastic polymer such as silicone rubber (e.g., polydimethylsiloxane; PDMS), polyurethane (PU), or polytetrafluoroethylene (PTFE), and thus may have flexible properties. However, embodiments according to the present specification are not limited thereto.

[0239] The upper stretchable substrate TPL may further include a touch portion. For example, the upper stretchable substrate TPL may be a touch panel or a touch member including a touch portion, but embodiments of the present specification are not limited thereto. The touch portion may sense a user's touch using a self-capacitance method or a mutual-capacitance method. The touch portion may include a plurality of touch electrodes, and the plurality of touch electrodes may form mutual capacitance or self-capacitance to detect touch by an object or person.

[0240] The second bonding layer 1120 may be provided between the light emitting element layer EL and the upper stretchable substrate TPL. The light emitting element layer EL and the upper stretchable substrate TPL may be bonded by the second bonding layer 1120.

[0241] The first stretchable plate CSB may be disposed on the upper stretchable substrate TPL. For example, the first stretchable plate CSB may be made of an elastic polymer such as silicone rubber (e.g., polydimethylsiloxane; PDMS), polyurethane (PU), or polytetrafluoroethylene (PTFE), and thus may have flexible properties. However, embodiments of the present invention are not limited thereto.

[0242] The third bonding layer 1130 may be disposed between the upper stretchable substrate TPL and the first stretchable plate CSB. The upper stretchable substrate TPL and the first stretchable plate CSB may be bonded by the third bonding layer 1130.

[0243] The protective stretchable plate PSB can be arranged on the first stretchable plate CSB. For example, the protective stretchable plate PSB can be made of an elastic polymer such as silicone rubber (e.g., polydimethylsiloxane; PDMS), polyurethane (PU) or polytetrafluoroethylene (PTFE), and thus can have flexible properties. However, the embodiments according to the present specification are not limited to this. Although the free volume fraction of the protective stretchable plate PSB can be about 50 or more, the embodiments of the present specification are not limited to this. The fourth bonding layer 1140 can be arranged between the first stretchable plate CSB and the protective stretchable plate PSB. The fourth bonding layer 1140 can connect or combine the first stretchable plate CSB with the protective stretchable plate PSB.

[0244] The nitrogen-reactive bonding layer BPP can be provided on the protective stretchable sheet PSB. The coating 500 can be provided on the nitrogen-reactive bonding layer BPP. The coating 500 can be formed by coating on the upper surface of the nitrogen-reactive bonding layer BPP. Since the coating 500 enables the front surface of the cover layer 300 to perform the touch function, the coating 500 can be implemented as a surface protection layer with stronger strength. When the coating 500 is formed as a surface protection layer, the coating 500 can be made of a resin with a relatively high hardness when cured, such as an acrylic resin, an epoxy resin, or a silicon-based compound, but the embodiments of this specification are not limited thereto. In addition, the coating 500 can be configured to be assigned an anti-fingerprint (AF) or anti-reflection (AR) function as needed. The coating 500 can be implemented by synthesizing a resin with such functions, or by forming various patterns (for example, a moth-eye pattern). Although the coating 500 can be a hard coating, the embodiments of this specification are not limited thereto.

[0245] Although the first bonding layer 1110, the second bonding layer 1120, the third bonding layer 1130, the fourth bonding layer 1140, and the nitrogen-reactive bonding layer BPP may each include a transparent adhesive, embodiments of the present specification are not limited thereto. For example, although the transparent adhesive may be a transparent resin (OCR) or a transparent adhesive (OCA), embodiments of the present specification are not limited thereto.

[0246] Although the thickness t2 of the fourth bonding layer 1140 may range from about 10 μm to about 150 μm, for example, embodiments of the present specification are not limited thereto. Although the thickness t3 of the nitrogen-reactive bonding layer BPP may range from about 10 μm to about 150 μm, embodiments of the present specification are not limited thereto. Although the thickness t5 of the second stretchable sheet PSB may range from about 5 μm to about 500 μm, embodiments of the present specification are not limited thereto.

[0247] The adhesive strength between the fourth bonding layer 1140 and the first stretchable sheet CSB may range from about 1 kgf / inch to about 3 kgf / inch.

[0248] Hereinafter, a third experiment will be described regarding the adhesive strength between glass and the first adhesive when the fifth sample is irradiated with ultraviolet rays. The material of the adhesive, the thickness of the adhesive, or the ultraviolet irradiation conditions of the third experiment do not limit the contents of this specification. The fifth sample is composed of glass, the first adhesive on the glass (with Figure 24 the same material as the second bonding layer 1140), a porous membrane (PDMS) on the first adhesive (with Figure 24 The same material as the protective stretchable sheet PSB), the second adhesive on the porous membrane (the same material as the Figure 24 The nitrogen reactive bonding layer BPP of the same material) and the base film on the second adhesive (with Figure 24 The first adhesive may have a thickness of about 10 μm. The porous membrane (PDMS) may have a thickness of about 350 μm. The fifth sample may be irradiated with ultraviolet light. Although the ultraviolet irradiation conditions may be a wavelength range of about 365 nm and at about 430 mW / cm 2 The energy density under the output condition is less than about 5000mJ / cm 2 , but the embodiments of the present specification are not limited thereto. Although ultraviolet rays may be irradiated once or twice, the embodiments of the present specification are not limited thereto.

[0249] It was confirmed that when the fifth sample was irradiated with ultraviolet rays, bubbles were generated on the entire surface of the fifth sample. In addition, the first adhesive could be easily peeled off from the glass. As a result of the third experiment, it was confirmed that since the porous film (PDMS) had a free volume fraction of about 50 or more even when the porous film (PDMS) had a thickness of about 350 μm, the bubbles (or nitrogen) generated from the second adhesive easily passed through the porous film (PDMS) and were located at the interface between the first adhesive and the glass, thereby easily peeling the first adhesive from the glass. Since the fifth sample used glass instead of Figure 23 and Figure 24 Because the first stretchable sheet CSB is formed, there may be a difference in the adhesive strength between the glass and the first adhesive, and between the first stretchable sheet CSB and the first adhesive, before and after ultraviolet irradiation. However, the results of the third experiment confirmed that even in the display device 12 according to the second embodiment, the nitrogen-reactive bonding layer BPP was irradiated with ultraviolet rays to weaken the adhesive strength between the first stretchable sheet CSB and the fourth bonding layer 740.

[0250] like Figure 25As shown, when the nitrogen-reactive bonding layer BPP is irradiated with ultraviolet light under the aforementioned irradiation conditions, the nitrogen-reactive bonding layer BPP' reacts with the ultraviolet light. The nitrogen-reactive bonding layer BPP' reacts with the ultraviolet light to generate nitrogen gas GAS. The generated nitrogen gas GAS can be located between the fourth bonding layer 1140 and the first stretchable sheet CSB. Because the nitrogen gas GAS is located between the fourth bonding layer 1140 and the first stretchable sheet CSB, the fourth bonding layer 1140 can be separated from the first stretchable sheet CSB by a predetermined distance, or a separation space can be formed.

[0251] Figure 25 The bonding strength between the fourth bonding layer 1140 and the first stretchable panel CSB may be less than about 0.3 kgf / inch.

[0252] like Figure 25 As shown, since the fourth bonding layer 1140 is separated from the first stretchable sheet CSB by a predetermined distance through the nitrogen GAS between the fourth bonding layer 1140 and the first stretchable sheet CSB to reduce the adhesive strength between the fourth bonding layer 1140 and the first stretchable sheet CSB, the fourth bonding layer 1140 can be easily peeled off from the first stretchable sheet CSB. In addition, the nitrogen GAS generated from the nitrogen reactive bonding layer BPP' can form a peeling space between the fourth bonding layer 1140 and the first stretchable sheet CSB. Therefore, according to another embodiment, the above-mentioned Figure 1 and Figure 2 Therefore, no physical damage to the first stretchable sheet CSB occurs.

[0253] The display device according to the various embodiments of the present specification can be applied to mobile devices, video phones, smart watches, watch phones, wearable devices, foldable devices, rollable devices, bendable devices, flexible devices, curved devices, sliding devices, variable devices, electronic notebooks, e-books, portable multimedia players (PMPs), personal digital assistants (PDAs), MP3 players, mobile medical devices, desktop PCs, laptops, netbooks, workstations, navigation systems, vehicle display devices, theater display devices, televisions, wallpaper devices, sign devices, gaming devices, laptops, displays, cameras, camcorders, home appliances, etc.

[0254] The display device according to various embodiments of the present specification can be described as follows.

[0255] A display device according to an embodiment of the present invention may include: a display panel; a cover layer on the display panel; and a bonding layer including a main bonding layer on the cover layer and a nitrogen-reactive bonding layer on the main bonding layer. The nitrogen-reactive bonding layer may have a nitrogen atom (N) content greater than that of the main bonding layer.

[0256] According to various embodiments of the present specification, the nitrogen-reactive bonding layer may have bonds between nitrogen atoms.

[0257] According to various embodiments of the present specification, the nitrogen-reactive bonding layer may include at least one of an azo compound, a diazo compound, and a pyrroloimidazole compound.

[0258] According to various embodiments of the present specification, the nitrogen-reactive bonding layer may be a UV-reactive bonding layer.

[0259] According to various embodiments of the present specification, the wavelength of the ultraviolet light may range from 320 nm to 400 nm.

[0260] According to various embodiments of this specification, the 2 The output is less than 5000mJ / cm 2 The energy density of ultraviolet radiation is irradiated.

[0261] According to various embodiments of the present specification, the cover layer may include glass. The adhesive strength between the primary bonding layer and the cover layer may range from 1.0 kgf / inch to 4.0 kgf / inch.

[0262] According to various embodiments of the present specification, the adhesive strength between the main bonding layer and the cover layer may be less than 0.3 kgf / inch according to the reaction of the nitrogen reactive bonding layer with ultraviolet rays.

[0263] According to various embodiments of the present specification, the nitrogen-reactive bonding layer may include an azo compound or a diazo compound, and the weight ratio of the azo compound or the diazo compound may be 2 wt % or less. According to various embodiments of the present specification, the nitrogen-reactive bonding layer may include a pyrroloimidazole compound, and the weight ratio of the pyrroloimidazole compound may be 5 wt % or less.

[0264] According to various embodiments of the present specification, the display panel may include a folding area, a first unfolding area disposed on one side of the folding area, and a second unfolding area disposed on the other side of the folding area.

[0265] A display device according to an embodiment of the present invention may include: a display panel; a main bonding layer on the display panel; a cover layer on the main bonding layer; and a nitrogen-reactive bonding layer on the cover layer. The nitrogen-reactive bonding layer may have a nitrogen atom content greater than that of the main bonding layer.

[0266] According to various embodiments of the present specification, the nitrogen-reactive bonding layer may have bonds between nitrogen atoms, and may include at least one of an azo compound, a diazo compound, and a pyrroloimidazole compound.

[0267] According to various embodiments of the present specification, the nitrogen-reactive bonding layer may be a UV-reactive bonding layer.

[0268] The display device according to various embodiments of the present specification may further include a polarizing layer between the display panel and the main bonding layer.

[0269] According to various embodiments of the present specification, the cover layer may include plastic. The bonding strength between the primary bonding layer and the polarizing layer may be greater than 0.8 kgf / inch.

[0270] According to various embodiments of the present specification, the adhesive strength between the main bonding layer and the polarizing layer may be less than 0.5 kgf / inch due to the reaction of the nitrogen-reactive bonding layer with ultraviolet rays.

[0271] A display device according to an embodiment of the present invention may include: a display panel; a first stretchable sheet on the display panel; a primary bonding layer on the first stretchable sheet; a second stretchable sheet on the primary bonding layer; and a nitrogen-reactive bonding layer on the second stretchable sheet. The nitrogen-reactive bonding layer may have a nitrogen atom content greater than that of the primary bonding layer.

[0272] According to various embodiments of the present specification, the nitrogen-reactive bonding layer may have bonds between nitrogen atoms, may contain at least one of an azo compound, a diazo compound, and a pyrroloimidazole compound, and may be a UV-reactive bonding layer.

[0273] According to various embodiments of the present disclosure, the bonding strength between the primary bonding layer and the first stretchable sheet may range from 1.0 kgf / inch to 3.0 kgf / inch. Depending on the reaction of the nitrogen-reactive bonding layer to ultraviolet light, the bonding strength between the primary bonding layer and the first stretchable sheet may be less than 0.3 kgf / inch.

[0274] According to various embodiments of the present specification, the thickness of the second stretchable sheet may range from 5 μm to 500 μm, and the free volume fraction of the second stretchable sheet may be 50 or greater.

[0275] A display device according to an embodiment of the present specification may include: a tray; a bonding layer on the tray; an LED chip on the bonding layer, wherein the bonding layer includes a base film, a nitrogen-reactive bonding layer between the base film and the tray, and a main bonding layer on the base film, wherein the nitrogen atom content of the nitrogen-reactive bonding layer is greater than the nitrogen atom content of the main bonding layer.

[0276] According to various embodiments of the present specification, the nitrogen-reactive bonding layer has bonds between nitrogen atoms, and the nitrogen-reactive bonding layer includes at least one of an azo compound, a diazo compound, and a pyrroloimidazole compound.

[0277] According to various embodiments of the present specification, the nitrogen-reactive bonding layer includes an azo compound or a diazo compound, and a weight ratio of the azo compound or the diazo compound is 2 wt % or less.

[0278] According to various embodiments of the present specification, the nitrogen-reactive bonding layer includes a pyrroloimidazole compound, and the weight ratio of the pyrroloimidazole compound is 5 wt % or less.

[0279] According to various embodiments of the present specification, the nitrogen-reactive bonding layer is a UV-reactive bonding layer.

[0280] According to various embodiments of the present specification, the bonding strength between the nitrogen reactive bonding layer and the tray is between 0.5 kgf / inch and 2.5 kgf / inch.

[0281] According to various embodiments of the present specification, the bonding strength between the nitrogen reactive bonding layer and the tray is less than 0.3 kgf / inch due to the reaction of the nitrogen reactive bonding layer with ultraviolet rays.

[0282] According to various embodiments of the present specification, the wavelength of ultraviolet light ranges from 320 nm to 400 nm, and the radiation intensity is less than 5000 mJ / cm 2 The energy density of ultraviolet radiation is irradiated.

[0283] According to the embodiment of the present disclosure, since the bonding layer is formed as a nitrogen-reactive bonding layer, the bonding layer can be easily peeled off from the base substrate by nitrogen gas on the interface with the base substrate.

[0284] Description of Reference Numerals

[0285] 10, 11, 12: Display device

[0286] 100: Display panel

[0287] 200: Polarization layer

[0288] 300: Covering

[0289] 400: film layer

[0290] 500: coating

[0291] 600: backplane layer

[0292] BPP: Nitrogen Reactive Bonding Layer

Claims

1. A display device, comprising: Display panel; a primary bonding layer on the display panel; a cover layer on the primary bonding layer; as well as a nitrogen reactive bonding layer on the cover layer, The nitrogen content of the nitrogen-reactive bonding layer is greater than that of the main bonding layer.

2. The display device according to claim 1, wherein The nitrogen-reactive bonding layer has bonds between the nitrogen atoms, and the nitrogen-reactive bonding layer includes at least one of an azo compound, a diazo compound, and a pyrroloimidazole compound.

3. The display device according to claim 2, wherein: The nitrogen-reactive bonding layer includes an azo compound or a diazo compound, and a weight ratio of the azo compound or the diazo compound is 2 wt % or less.

4. The display device according to claim 2, wherein The nitrogen-reactive bonding layer is an ultraviolet-reactive bonding layer. The display device according to claim 4 , further comprising a polarizing layer between the display panel and the main bonding layer. The display device according to claim 5 , wherein: The bonding strength between the main bonding layer and the polarizing layer is greater than 0.8 kgf / inch.

7. The display device according to claim 6, wherein: According to the reaction of the nitrogen-reactive bonding layer and the ultraviolet rays, the bonding strength between the main bonding layer and the polarizing layer is less than 0.5 kgf / inch.

8. The display device according to claim 4, wherein The wavelength of the ultraviolet light ranges from 320 nm to 400 nm.

9. The display device according to claim 8, wherein Less than 5000mJ / cm 2 The ultraviolet rays are irradiated with an energy density of .

10. The display device according to claim 2, wherein: The nitrogen-reactive bonding layer includes a pyrroloimidazole compound, and a weight ratio of the pyrroloimidazole compound is 5 wt % or less.

Images