Flexible display panel

Abstract

Disclosed herein is a flexible display panel including a glass substrate, a circuit layer disposed on the glass substrate and configured to drive a pixel, a light emitting element layer disposed on the circuit layer, an encapsulation layer covering the circuit layer and the light emitting element layer, a polarizing plate disposed on the encapsulation layer, and a cover glass disposed on the polarizing plate. At least one of the glass substrate and the cover glass includes a buffer portion. The buffer portion includes an organic filler and glass. The glass of the buffer portion has a thickness less than or equal to a thickness of the glass substrate and includes a pattern of a specific shape. Thus, due to the glass in the buffer portion, rigidity of a folding portion where the buffer portion is located can be increased.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2020-0081696, filed on July 2, 2020, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to a flexible display panel. Background Technology

[0004] Based on the material of the light-emitting layer, electroluminescent display devices are broadly classified into inorganic light-emitting display devices and organic light-emitting display devices. Active-matrix organic light-emitting display devices include organic light-emitting diodes (hereinafter referred to as "OLEDs"). OLEDs emit light themselves, possessing fast response times and advantages such as high luminous efficiency, brightness, and viewing angle. In organic light-emitting display devices, OLEDs are formed in pixels. Due to their fast response times, excellent luminous efficiency, brightness, and viewing angle, and ability to display true black, organic light-emitting display devices excel in contrast and color reproduction.

[0005] Organic light-emitting display devices do not require a backlight unit and can be implemented on plastic substrates, thin glass substrates, or metal substrates made of flexible materials. Therefore, flexible displays can indeed be realized as organic light-emitting display devices.

[0006] The screen size of a flexible display can be changed by rolling, folding, and bending the flexible display panel. Flexible displays can be made into rollable displays, foldable displays, bendable displays, sliding displays, and more. Flexible displays can be used not only in mobile devices such as smartphones and tablets (PCs), but also in televisions (TVs), vehicle displays, and wearable devices, and the application areas of flexible display devices are expanding.

[0007] Flexible displays enable bezel-bending displays, where the non-display area is folded down using a flexible panel structure to minimize the bezel area. Furthermore, flexible displays can be integrated into information devices with structures capable of changing screen size. Because information devices utilize flexible displays to increase screen size, multitasking can be achieved by running more than one application or piece of content. Summary of the Invention

[0008] The flexible substrate used in flexible displays can be made of flexible materials, such as polyimide (PI) film substrates. During the manufacturing process of flexible display panels, circuit layers and light-emitting elements can be formed on the PI film while a carrier substrate with high rigidity and heat resistance is bonded beneath it. Since the carrier substrate is only needed during manufacturing, it can be separated from the PI film substrate after all the layers required to drive the pixels have been formed on the PI film. The carrier substrate can be separated from the PI film substrate using a laser lift-off process.

[0009] The manufacturing process of flexible display panels is expensive due to the use of costly laser equipment. Furthermore, the surface roughness of the PI film and the foreign matter generated when the laser irradiates the entire surface of the PI film substrate to peel it off may cause defects in subsequent processes.

[0010] Alternatively, the folding section can be made solely of organic materials to allow the flexible display panel to bend flexibly. In this case, creases or hinge marks may appear due to the weak rigidity of the folding section.

[0011] This disclosure aims to address all the aforementioned necessities and issues.

[0012] This disclosure relates to a flexible display panel that does not require the use of expensive laser equipment, thereby preventing defects caused by the process of peeling the PI film from the carrier substrate and increasing the rigidity of the folded portion.

[0013] It should be noted that the purpose of this disclosure is not limited to the above-described purposes, and other purposes of this disclosure will be apparent to those skilled in the art from the following description.

[0014] According to one aspect of this disclosure, a flexible display panel is provided, comprising: a glass substrate; a circuit layer disposed on the glass substrate and configured to drive pixels; a light-emitting element layer disposed on the circuit layer; an encapsulation layer covering the circuit layer and the light-emitting element layer; a polarizing plate disposed on the encapsulation layer; and a cover glass disposed on the polarizing plate. At least one of the glass substrate and the cover glass may include a buffer portion. The buffer portion may include organic fillers and glass. The glass of the buffer portion may have a thickness less than or equal to the thickness of the glass substrate and may include a pattern of a specific shape.

[0015] According to another aspect of this disclosure, a flexible display panel is provided, comprising: a glass substrate; a circuit layer disposed on the glass substrate and configured to drive pixels; a light-emitting element layer disposed on the circuit layer; an encapsulation layer covering the circuit layer and the light-emitting element layer; a polarizing plate disposed on the encapsulation layer; and a cover glass disposed on the polarizing plate. At least one of the glass substrate and the cover glass may include a buffer portion. The buffer portion may include an organic filler and glass. The ratio of the thickness of the organic filler in the buffer portion to the thickness of the glass may be in the range of 6 to 10:4 to 9. Attached Figure Description

[0016] The above and other objects, features, and advantages of this disclosure will become more apparent to those skilled in the art from the detailed description of exemplary embodiments thereof with reference to the accompanying drawings, in which:

[0017] Figures 1 to 3 It is a diagram illustrating a flexible display panel including the folded section;

[0018] Figure 4 This is a cross-sectional view illustrating a flexible display panel according to the first embodiment of the present disclosure;

[0019] Figure 5 This is a cross-sectional view illustrating a flexible display panel according to the second embodiment of this disclosure;

[0020] Figure 6 This is a plan view illustrating an example of a glass pattern;

[0021] Figure 7 The diagram shows the following: Figure 6 A cross-sectional view of the glass substrate taken by line "II";

[0022] Figure 8 This is a plan view of another example illustrating a glass pattern;

[0023] Figure 9 and Figure 10 It is a diagram illustrating the etching method for a glass substrate;

[0024] Figure 11 This is a cross-sectional view illustrating a flexible display panel according to the third embodiment of this disclosure;

[0025] Figure 12 This is a cross-sectional view illustrating a flexible display panel according to the fourth embodiment of this disclosure;

[0026] Figure 13 This is a cross-sectional view illustrating a flexible display panel according to the fifth embodiment of this disclosure;

[0027] Figure 14 It is a diagram. Figure 13 A plan view of an example of beads dispersed in a beaded membrane, shown in the figure;

[0028] Figure 15A and Figure 15B This is a cross-sectional view illustrating a flexible display panel according to the sixth embodiment of this disclosure;

[0029] Figure 16A and Figure 16B This is a cross-sectional view illustrating a flexible display panel according to the seventh embodiment of this disclosure;

[0030] Figure 17 This is a cross-sectional view illustrating a flexible display panel according to the eighth embodiment of this disclosure;

[0031] Figure 18 It is a diagram Figure 17 An enlarged view of the wedge-shaped sidewall portion A of the substrate;

[0032] Figure 19 This is a diagram illustrating the process steps for manufacturing a wedge-shaped sidewall of a glass substrate according to an embodiment of the present disclosure;

[0033] Figure 20 These are illustrations of various examples of wedge-shaped sidewalls on a glass substrate;

[0034] Figure 21 A cross-sectional photograph of a glass substrate is shown, illustrating the conical surface when the thickness of the glass substrate is reduced due to the etching process of the glass substrate.

[0035] Figure 22 This is a block diagram illustrating an example of a display device according to one embodiment of the present disclosure;

[0036] Figure 23 This is a block diagram illustrating an example of a display device according to another embodiment of the present disclosure;

[0037] Figure 24A and Figure 24B It is a diagram. Figure 23 The diagram shows an example of a folded display device;

[0038] Figure 25 It is a schematic block diagram illustrating the configuration of a driver integrated circuit (IC);

[0039] Figure 26 This is a circuit diagram illustrating an example of a pixel circuit;

[0040] Figure 27 It is a diagram Figure 26 A diagram showing the driving method of the pixel circuit; and

[0041] Figure 28 This is a detailed cross-sectional view illustrating the cross-sectional structure of a display panel according to one embodiment of the present disclosure. Detailed Implementation

[0042] The advantages and features of this disclosure, as well as the methods for implementing these advantages and features, will become clearer from the embodiments described below with reference to the accompanying drawings. However, this disclosure is not limited to the embodiments described below, but can be implemented in various different forms. Rather, these embodiments will complete the disclosure of this disclosure and enable those skilled in the art to fully understand its scope. This disclosure is limited only by the scope of the appended claims.

[0043] The shapes, dimensions, ratios, angles, quantities, etc., shown in the accompanying drawings used to describe embodiments of this disclosure are merely examples, and this disclosure is not limited thereto. Throughout the application, the same reference numerals generally denote the same elements. Furthermore, in describing this disclosure, detailed descriptions of known related technologies may be omitted to avoid unnecessarily obscuring the subject matter of this disclosure.

[0044] Unless used with the term "only," terms such as "including," "comprising," "having," "consisting of," etc., as used herein are generally intended to allow for the addition of other components. Unless otherwise expressly stated, any singular reference may include the plural.

[0045] Even if not explicitly stated, components are interpreted as including the normal tolerance range.

[0046] When using terms such as “on top of,” “above,” “below,” or “adjacent to” to describe the positional relationship between two components, one or more components may be located between the two components, unless the term is used in conjunction with the terms “immediately adjacent” or “directly.”

[0047] The terms “first”, “second”, etc., can be used to distinguish components from each other, but the function or structure of a component is not limited by the ordinal number preceding the component or the component name.

[0048] Throughout this disclosure, the same reference numerals may refer to substantially the same elements.

[0049] The following implementation methods may be combined or integrated with each other in whole or in part, and may be associated and operated in various technical ways. The implementation methods may be performed independently or in conjunction with each other.

[0050] In the following text, "display panel" can be interpreted as having the same meaning as "flexible display panel." "Fold" refers to the curved portion of a flexible display panel.

[0051] In the following, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0052] The display panel disclosed herein is manufactured based on a flexible, thin glass substrate. The glass substrate may be a glass film with a thickness of 0.2 mm or less. Commercially available reinforced glass films may be used as the glass film. Hereinafter, the glass substrate may be interpreted as the glass film.

[0053] like Figure 1 As shown, the display panel 100 has a width in the X-axis direction, a length in the Y-axis direction, and a constant thickness in the Z-axis direction. Since the circuit layer and the light-emitting element layer can be disposed on the glass substrate, the thickness of the display panel 100 can be greater than the thickness of the glass substrate. The width and length of the display panel 100 can be set to various design values ​​depending on the application of the display device. For example... Figure 1 As shown, the display panel 100 can be manufactured as a generally rectangular plate, but this disclosure is not limited thereto. For example, the display panel 100 can be manufactured as different panels including curved portions.

[0054] The display panel 100 includes non-foldable portions 101 and 102, and a foldable portion 100f disposed between the non-foldable portions 101 and 102. The foldable portion 100f may be formed as a fold line that extends from one end of the display panel 100 to the other end in the Y-axis direction (i.e., the length direction of the display panel 100) or in the X-axis direction (i.e., the width direction of the display panel). The fold line includes a buffer portion, which will be described in the embodiments. The display panel 100 can be bent or folded due to an external force based on the foldable portion 100f. When the thickness of the glass substrate of the display panel 100 is small, the display panel 100 can be flexibly bent with a sufficiently large curvature even with a small force.

[0055] According to this disclosure, the folded portion 100f includes glass with a thickness less than or equal to the thickness of the glass in each of the non-folded portions 101 and 102, thereby increasing the rigidity of the folded portion 100f and reducing the difference in refractive index between the folded portion 100f and the non-folded portions 101 and 102. According to this disclosure, an organic material can be added to at least a portion of the folded portion 100f to allow the folded portion 100f to be easily bent within the display panel 100. As this organic material, a resin material with high tensile strength can be used, such as one of polyurethane, acrylic, and silicone synthetic rubber, or a mixture of two or more of them. Examples of silicone synthetic rubber may include polydimethylsiloxane (PDMS).

[0056] Display panel 100 may include a folded portion 100f and non-folded portions 101 and 102. One or more of the non-folded portions 101 and 102 may include a display portion on which an input image is reproduced. The non-folded portions 101 and 102 may have different sizes. Figure 1 In the example, the first non-folded portion 101 may include a pixel array for displaying an image. The second non-folded portion 102 may include an integrated circuit (IC) mounting area thereon on which a driver IC for driving the pixels is mounted. At least a portion of the second non-folded portion 102 may include a pixel array for displaying an image or preset additional information.

[0057] When the second non-folded portion 102 is used as the IC mounting area, when the folded portion 100f is bent at a high curvature, the second non-folded portion 102 can be folded outward to the surface opposite to the display surface on which the image is displayed, such as the display surface of the first non-folded portion 101. Figure 2 and Figure 3 The example illustrates a folded portion 100f disposed between three non-folding portions 101, 102, and 103 in a foldable display. Each of the non-folding portions 101, 102, and 103 includes an array of pixels for displaying images or information. As described above, each of the folded portions 100f may comprise glass and organic materials.

[0058] Figure 4 This is a cross-sectional view illustrating a flexible display panel according to the first embodiment of this disclosure.

[0059] Reference Figure 4 The display panel 100 includes: a glass substrate 10; an organic film 12 disposed on the glass substrate 10; and a circuit layer 14 and a light-emitting element layer 16 stacked on the organic film 12. The display panel 100 may further include: an encapsulation layer 18 covering the circuit layer 14 and the light-emitting element layer 16; a polarizing plate 20; and a cover window 22. A touchscreen in which a touch sensor is disposed can be implemented on the display panel 100. The circuitry of the touch sensor (not shown in the figure) can be disposed between the encapsulation layer 18 and the polarizing plate 20.

[0060] The organic film 12 may be a film selected from the group consisting of polyimide-based polymers, polyester-based polymers, silicone-based polymers, acrylic-based polymers, polyolefin-based polymers, and copolymers thereof. Because polyimide has acid and heat resistance, it can be applied in high-temperature processes of the circuit layer 14 and the light-emitting element layer 16. In the embodiment described below, since the circuit layer 14 can be formed directly on the glass substrate 10, the organic film 12 can be omitted.

[0061] Circuit layer 14 may include pixel circuitry connected to data lines, gate lines, and power lines, as well as gate drivers connected to the gate lines. The pixel circuitry and gate drivers may include circuit elements such as thin-film transistors (TFTs) and capacitors. To reduce the tension and stress applied to circuit layer 14 when the fold FO is bent, circuit layer 14 in the fold FO may consist only of lines such as data lines, gate lines, and power lines.

[0062] The light-emitting element layer 16 may include an organic light-emitting diode (OLED) driven by driving elements of the pixel circuitry. The OLED includes an organic compound layer formed between an anode and a cathode. The organic compound layer may include a hole injection layer (HIL), a hole transport layer (HTL), an emissive layer (EML), an electron transport layer (ETL), and an electron injection layer (EIL), but this disclosure is not limited thereto. When a voltage is applied to the anode and cathode of the OLED, holes passing through the HTL and electrons passing through the ETL move to the EML to form excitons, thereby emitting visible light from the EML. The light-emitting element layer 16 may also include an array of color filters that selectively transmit red, green, and blue wavelengths.

[0063] The light-emitting element layer 16 and the circuit layer 14 may be covered by a protective layer, which is omitted from the figure. Each of the protective layer and the encapsulation layer 18 may be formed of an inorganic layer, or may have a structure in which organic and inorganic layers are stacked alternately, the inorganic layer being made of glass, metal, or alumina (AlO2). x It is made of silicon (Si) based materials. The inorganic layer blocks the penetration of moisture or oxygen. The organic layer planarizes the surface of the inorganic layer. When the organic and inorganic layers are stacked in multiple layers, the movement path of moisture or oxygen becomes longer than that of a single layer, thereby effectively blocking the penetration of moisture / oxygen that affects the light-emitting element layer 16.

[0064] The polarizer 20 can be bonded to the encapsulation layer 18 using adhesive 19. The polarizer 20 improves the outdoor visibility of the display device. The polarizer 20 reduces light reflected from the surface of the display panel 100 and blocks light reflected from the metal of the circuit layer 14, thereby improving pixel brightness. The polarizer 20 can be implemented as a linear polarizer, a polarizer with a phase retardation film, or a circular polarizer. A transparent cover window 22 can be provided on the polarizer 20.

[0065] The glass substrate 10 can be made of plate-shaped alkali-free glass or plate-shaped non-alkali glass. The glass substrate 10 can be divided into a folded portion FO and a non-folded portion NFO. The non-folded portion NFO of the glass substrate 10 is made of glass only.

[0066] The folded portion FO of the glass substrate 10 includes one or more buffer portions. Each buffer portion includes glass 40 and an organic filler 30. For example, a portion of the glass 40 can be removed from the folded portion FO of the glass substrate 10 to form a hole 10a, and the hole 10a can be filled with the organic filler 30. The organic filler 30 may comprise a resin material with high tensile strength. The glass 40 of the folded portion FO may be in contact with an organic film 12. When the organic film 12 is omitted, the glass 40 of the folded portion FO may be in contact with the circuit layer 14.

[0067] The organic filler 30 improves the tensile strength of the fold portion FO, thereby absorbing the stress applied to the glass substrate 10 even when the display panel 100 is bent at a high curvature. The glass 40 of the fold portion FO enhances the rigidity of the glass substrate 10 in the fold portion FO. The combination of the organic filler 30 and the glass 40 makes the fold portion FO easy to bend at a high curvature in the display panel 100 and enhances the rigidity of the glass substrate 10, thereby reducing the strain of the glass substrate 10. Therefore, according to this disclosure, even when the display panel 100 is folded at a high curvature, the strain of the glass substrate 10 can be reduced to prevent the appearance of creases or hinge marks.

[0068] exist Figure 4 In this case, the glass thickness tf of the folded portion FO is less than the glass thickness tnf of the non-folded portion NFO, but this disclosure is not limited thereto. For example, when the glass 40 is patterned in the folded portion FO and the recessed portion (i.e., hole 10a) of the folded portion FO is filled with organic filler 30, the thickness of the glass pattern can be set to be less than or equal to the thickness of the glass 40 in the non-folded portion NFO. Figure 5 The example shows a glass pattern in the folded section FO.

[0069] Figure 5 This is a cross-sectional view illustrating the flexible display panel according to the second embodiment of this disclosure. Figure 5 In this document, components that are substantially the same as those in the first embodiment are assigned the same reference numerals, and their detailed descriptions are omitted herein.

[0070] Reference Figure 5 The folded portion FO of the glass substrate 10 includes a glass pattern 41 and an organic filler 31 that fills the holes 10a of the folded portion FO. The glass pattern 41 disposed in the holes 10a of the folded portion FO can contact the organic film 12 or the circuit layer 14.

[0071] like Figure 6 As shown, when the display panel 100 is viewed from above, the hole 10a of the folding portion FO may be in the form of a line formed along the glass pattern 41, which is patterned as a strip parallel to the folding line FL in the X-axis direction, but the present disclosure is not limited thereto.

[0072] Figure 6 This is a plan view illustrating an example of a glass pattern. Figure 7 The diagram shows the following: Figure 6 A cross-sectional view of the glass substrate taken by line "II".

[0073] like Figure 6 As shown, when the length direction (i.e., the X-axis direction) of the glass pattern 41 is parallel to the fold line FL, the folded portion FO in the display panel 100 is prone to bending in the Y-axis direction perpendicular to the fold line FL. In addition, due to the increased rigidity of the glass pattern 41 in the X-axis direction parallel to the fold line FL, the display panel 100 is less prone to bending in the X-axis direction.

[0074] Depending on the required curvature and rigidity in the folded portion FO, the thickness of the glass pattern 41 can be appropriately set to be less than or equal to the glass thickness tnf of the non-folded portion NFO. Figure 7 (a) An example in which the thickness of the illustrated glass pattern 41 is the same as the glass thickness tnf of the non-folded part NFO. Figure 7 (b) illustrates an example where the thickness of the glass pattern 41 is less than the glass thickness tnf of the non-folded portion NFO. The thickness and spacing of the glass pattern 41 can be controlled by etching the glass substrate 10.

[0075] Figure 8 This is a plan view of another example illustrating a glass pattern.

[0076] Reference Figure 8 The glass patterns 42 and 43 disposed in the holes 10a of the folded portion FO can be patterned in the form of square prisms or cylinders arranged in a matrix. The glass patterns 42 and 43 are disposed in the holes 10a of the folded portion FO and filled with organic fillers 32 and 33. The folded portion FO with this structure can be bent at the boundaries of the fold lines FL in the biaxial directions (X-axis and Y-axis directions) and its rigidity can be increased due to the glass patterns 42 and 43 in the biaxial directions.

[0077] According to this disclosure, in order to reduce the thickness of the glass substrate 10 or to process the hole 10a of the folded portion FO in the glass substrate 10 or the sidewall of the edge of the glass substrate 10 into a desired shape, the glass substrate 10 can be etched by a wet etching method.

[0078] Figure 9 and Figure 10 This is a diagram illustrating the etching method of the glass substrate 10.

[0079] A mask film 11 can be disposed on one surface of the glass substrate 10, and an etch-resistant film 50 can be disposed on the other surface of the glass substrate 10. The mask film 11 and the etch-resistant film 50 can be organic films applied to or bonded to the glass substrate 10. The etch-resistant film 50 can be used as an etch stop layer in the etching process and can be the organic film 12 described in the above embodiments. The mask film 11 may include openings that expose the glass substrate 10 to the etchant (etching solution) used for glass etching. The shape, thickness, and spacing of the glass patterns 40 to 43 can be determined based on the shape and spacing of the openings and the etching processing time. The mask film 11 can be removed after the etching process.

[0080] According to this disclosure, the glass substrate 10 can be etched such that an etchant is sprayed onto the glass substrate 10 which is bonded with the mask film 11, or the glass substrate 10 can be placed in a water tank containing an etchant by an immersion method.

[0081] Etching agent is supplied to the glass substrate 10 through openings in the mask film 11. For example... Figure 9 As shown in (a), the glass substrate 10, exposed by the openings in the mask film 11, reacts with the etchant and begins to be etched. Figure 9 As shown in (b), the glass substrate 10 exposed to the etchant is etched, thereby forming a hole 10a in the glass substrate 10, and as the etching process time passes, as... Figure 9 As shown in (c), the depth of hole 10a increases. When the etching time in the etching process becomes longer, as... Figure 9 As shown in (d) and (e), the etchant penetrates between the glass substrate 10 and the anti-etching film 50, and between the glass substrate 10 and the mask film 11, thereby forming a tapered surface on the sidewall glass of the hole 10a.

[0082] Using this glass etching method, a hole 10a and a residual glass film (or glass pattern) can be formed at a desired depth h in the folded portion FO. For example... Figure 10 As shown, when the aperture of the mask film 11 is small, the depth h of the hole 10a formed in the glass substrate 10 decreases. In this case, the thickness of the glass pattern 41 provided in the hole 10a increases, and the number of glass patterns 41 can be increased. On the other hand, when the aperture of the mask film 11 is large, the depth h of the hole 10a formed in the glass substrate 10 increases, and the thickness of the glass pattern 41 decreases.

[0083] In the flexible display panel of this disclosure, glass is retained in both the folded portion FO and the non-folded portion NFO. Therefore, the surface rigidity in the folded portion FO is enhanced, thereby reducing creases or hinge marks.

[0084] Figure 11This is a cross-sectional view illustrating a flexible display panel according to a third embodiment of this disclosure. Figure 11 In this document, components that are substantially the same as those in the above embodiments are assigned the same reference numerals, and their detailed descriptions are omitted.

[0085] Reference Figure 11 The display panel 100 includes a glass substrate 10, an organic film 12 disposed on the glass substrate 10, and a circuit layer 14 and a light-emitting element layer 16 stacked on the organic film 12. The display panel 100 may also include an encapsulation layer 18, a polarizing plate 20, and a cover window 22 covering the circuit layer 14 and the light-emitting element layer 16.

[0086] The glass substrate 10 can be divided into a folded portion FO and a non-folded portion NFO. The folded portion FO of the glass substrate 10 includes one or more buffer portions, each including a hole 10a filled with an organic filler 70. Glass can be retained in the hole 10a. The glass can be in the form of a residual film left after an etching process or in the form of a glass pattern. Beads (not shown in the accompanying drawings) can be added to the organic filler 70 in the buffer portion of the glass substrate 10. The beads can be made of quantum dot (QD) material.

[0087] The cover window 22 may include one or more buffer portions. Each buffer portion may include a hole 22a filled with an organic filler 60. The hole 22a of the cover window 22 may be formed by partially etching the cover window 22. The hole 22a includes beads 62 made of inorganic material. The beads 62 may increase the elastic modulus of the folded portion FO, thereby increasing the rigidity of the folded portion FO and reducing the difference in refractive index between the non-folded portion NFO and the folded portion FO. The beads 62 may scatter light to resolve the phenomenon observed in the folded portion FO caused by the organic fillers 60 and 70 filling the holes 10a and 22a.

[0088] Due to the organic fillers 60 and 70, the color reproduction in the folded portion FO may be degraded. To address this issue, bead 62 may include QD material.

[0089] QD materials can be materials made from group II-VI semiconductor compounds, group III-V semiconductor compounds, group IV-VI semiconductor compounds, group IV elements or compounds, or combinations thereof. For example, II-VI semiconductor compounds can be selected from the group consisting of: binary compounds selected from the group consisting of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, and mixtures thereof; and compounds selected from the group consisting of CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, and CdZnSe. Ternary compounds selected from the group consisting of CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe and mixtures thereof; and quaternary compounds selected from the group consisting of CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe and mixtures thereof. III-V semiconductor compounds may be selected from the group consisting of: binary compounds selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb and mixtures thereof; ternary compounds selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP and mixtures thereof; and quaternary compounds selected from the group consisting of GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb and mixtures thereof. IV-VI semiconductor compounds may be selected from the group consisting of: binary compounds selected from SnS, SnSe, SnTe, PbS, PbSe, PbTe and mixtures thereof; ternary compounds selected from SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe and mixtures thereof; and quaternary compounds selected from SnPbSSe, SnPbSeTe, SnPbSTe and mixtures thereof.Group IV elements or compounds may be selected from the following groups: elemental compounds selected from the group consisting of Si, Ge and mixtures thereof; and binary compounds selected from the group consisting of SiC, SiGe and mixtures thereof.

[0090] QD materials are semiconductor materials with crystal structures having dimensions smaller than the Bohr exciton radius. Although QD materials contain a large number of electrons, the number of free electrons ranges from approximately 1 to 100. QD is generated by photon excitation. When light shines from the light-emitting element layer 16 onto the QD material, photons in the QD material are excited and transition to higher energy bands, causing either a fallback or photon recombination to produce light.

[0091] Because the energy levels of electrons in QD materials are discontinuous, QD materials exhibit electrical and optical properties different from those of bulk semiconductors that form continuous bands. QD beads have different energy levels depending on their size. The band gap can vary depending on the size of the QD beads. By simply adjusting the size of the QD beads 62 added to the folded portion FO, the light emission wavelength can be controlled within the visible light range. Therefore, according to this disclosure, not only can the rigidity of the folded portion FO be enhanced using QD beads 62, but the color reproducibility of the folded portion FO can also be improved using organic fillers 60 and 70, and the viewing angle can be increased.

[0092] Although Figure 11 The details are omitted, but beads can be added to the folded portion FO of the glass substrate 10, and QDs can be included in the beads.

[0093] The image quality of a liquid crystal display device can be improved using QD (Quick Diffraction). In this case, the QD film should be located between the backlight unit and the polarizer below the display panel. When the QD film is located between the upper and lower polarizers of the display panel, the polarized light passing through the lower polarizer is deflected due to the QD film, causing the image to be incorrectly reproduced on the display panel. In contrast, according to this disclosure, the QD material is disposed on the display panel 100. In particular, as... Figure 11 As shown, it should be noted that the display panel 100 has a structure in which the QD material is in contact with the polarizer 20 disposed on the light-emitting element layer 16, or the QD material is disposed on the polarizer 20.

[0094] Figure 12 This is a cross-sectional view illustrating a flexible display panel according to the fourth embodiment of this disclosure. Figure 12 In this document, components that are substantially the same as those in the above embodiments are assigned the same reference numerals, and their detailed descriptions are omitted.

[0095] Reference Figure 12The cover window 22 may include one or more beads 23 in the fold FO. The beads 23 may include QD material to improve color reproduction and the viewing angle of the fold FO. By adjusting the size of the QD material, the wavelength of light emitted from the QD material can be changed to a desired wavelength.

[0096] Figure 13 This is a cross-sectional view illustrating a flexible display panel according to a fifth embodiment of the present disclosure. Figure 13 In this document, components that are substantially the same as those in the above embodiments are assigned the same reference numerals, and their detailed descriptions are omitted. Figure 14 It is a diagram. Figure 13 A plan view of an example of beads dispersed in a beaded membrane is shown.

[0097] Reference Figure 13 and Figure 14 The display panel 100 includes a bead film 21 disposed between the polarizer 20 and the cover window 22. Multiple beads 21a, comprising inorganic materials or QD materials, can be dispersed in the bead film 21. The beads 21a can be disposed in the non-folded region NFO and the folded region FO, or, as... Figure 14 As shown, beads 21a are only disposed in the folded region FO. The QD beads 21a dispersed in the bead film 21 improve the color reproduction and viewing angle of the image reproduced in the pixel array.

[0098] The inventors of this application repeatedly simulated to examine the stress and strain generated in the folded portion of the display panel when the thicknesses of the organic filler and glass varied. According to the simulation results, when the ratio of the thickness of the organic filler to the thickness of the glass in the folded portion FO was 6:4, an ideal neutral state with no stress was measured when the folded portion FO was bent at the desired curvature. According to the simulation results, when the ratio of the thickness of the organic filler to the thickness of the glass was in the range of 6 to 10:4 to 9, a neutral state or a strain similar to a neutral state was confirmed. Therefore, the thickness of the organic filler and the thickness of the glass in the folded portion FO can be set according to the above thickness ratio.

[0099] When the fold portion FO of the display panel 100 is bent, the force applied to the fold portion FO is different at each location because the curvature of the fold portion FO varies. Therefore, the required tensile strength and rigidity at each location of the fold portion FO may differ. Considering the above description, as... Figure 17 and Figure 18 As shown, when the folding part FO is folded, the thickness of the glass can be set differently depending on the position of the folding part FO, taking into account the differences in force and strain applied to each position of the folding part FO.

[0100] Depending on the application, the folds of a flexible display panel may need to be reinforced; in contrast, tensile strength can be considered important.

[0101] Figure 15A and Figure 15B This is a cross-sectional view illustrating a flexible display panel according to the sixth embodiment of this disclosure. Figure 15A and Figure 15B In the figure, "t01" refers to the thickness of organic fillers 81 and 82, and "t02" refers to the thickness of the glass.

[0102] like Figure 15A As shown, the folded portion FO of the display panel 100 may include multiple buffer portions CGF1 and CGF2. Buffer portions CGF1 and CGF2 include holes filled with organic fillers 81 and 82, and glass 91 and 92. Glass 91 and 92 may be in the form of a residual film or pattern as described in the above embodiment. When the folded portion FO is bent, the first buffer portion CGF1 located in the portion with the greatest curvature may have the longest length, or the glass thickness t02 may be set to be larger. In contrast, the second buffer portion CGF2 located in the portion with a relatively smaller curvature may have a glass thickness t02 set to be relatively smaller.

[0103] like Figure 15B As shown, the folding portion FO of the display panel 100 may include a buffer portion CGFO having partially different glass thicknesses. The buffer portion CGFO includes holes filled with organic filler 80 and glass 90. The glass 90 may be in the form of a residual film or pattern as described in the above embodiment. When the folding portion FO is bent, the thickness t02 of the glass located in the portion with the maximum curvature can be set to be larger, while the thickness t02 of the glass located in the portion with a relatively smaller curvature can be set to be smaller. When the folding portion is frequently folded, for example in a foldable display, Figure 15A and Figure 15B The example shown can further enhance the rigidity of sections with greater curvature, thereby preventing crease marks or hinge marks from being visible, and can improve the tensile strength of sections with relatively smaller curvature.

[0104] Figure 16A and Figure 16B This is a cross-sectional view illustrating a flexible display panel according to the seventh embodiment of this disclosure.

[0105] like Figure 16AAs shown, the folded portion FO of the display panel 100 may include multiple buffer portions CGF1 and CGF2. Buffer portions CGF1 and CGF2 include holes filled with organic fillers 81 and 82, and glass 91 and 92. Glass 91 and 92 may be in the form of a residual film or pattern as described in the above embodiment. When the folded portion FO is bent, the first buffer portion CGF1 located in the portion with the greatest curvature may have the longest length, or the glass thickness t02 may be set to a smaller value. In contrast, the second buffer portion CGF2 located in the portion with a relatively smaller curvature may have a relatively larger glass thickness t02.

[0106] like Figure 16B As shown, the folded portion FO of the display panel 100 may include a buffer portion CGFO having partially different glass thicknesses. The buffer portion CGFO includes holes filled with organic filler 80 and glass 90. The glass 90 may be in the form of a residual film or pattern as described in the above embodiment. When the folded portion FO is bent, the thickness t02 of the glass located in the portion with the maximum curvature may be set to be smaller, while the thickness t02 of the glass located in the portion with a relatively small curvature may be set to be larger.

[0107] When there is no situation where the folding part unfolds immediately after folding, such as in a monitor with a curved bezel. Figure 16A and Figure 16B The example shown can improve the tensile strength in a section with greater curvature in order to reduce the stress in the fold, and improve the rigidity in a section with relatively smaller curvature.

[0108] In the above embodiments, the glass substrate 10 can be made to be thin enough to bend to the curvature required for the application of the product. The thin glass substrate 10 is flexible and bendable, and has acid and heat resistance properties. Therefore, according to this disclosure, the circuit layer 14 can be directly mounted on the thin glass substrate 10 without the organic film 12.

[0109] The thin glass substrate 10 is flexible, but when an impact is applied to the sidewalls and corners, cracks or breaks may occur in the thin glass substrate 10. According to this disclosure, as Figure 17 and Figure 18 As shown, in order to distribute externally applied impacts or stresses to the fragile portions of the thin glass substrate 10, the sidewalls of the edge of the glass substrate 10 can be treated in the form of wedges.

[0110] Figure 17 This is a cross-sectional view illustrating a flexible display panel according to the eighth embodiment of this disclosure. Figure 18 It is a diagram Figure 17 An enlarged view of the wedge-shaped sidewall portion A. Figure 17 and Figure 18 In this embodiment, the buffer portion of the folded portion FO is omitted. In this embodiment, the structure of the buffer portion can be implemented as any one or a combination of those described in the above embodiments.

[0111] Reference Figure 17 and Figure 18 The display panel 100 includes a glass substrate 10, a circuit layer 14 stacked on the glass substrate 10, and a light-emitting element layer 16. The display panel 100 may also include an encapsulation layer 18, a polarizer 20, and a cover window 22 covering the circuit layer 14 and the light-emitting element layer 16. The display panel 100 may also include a touch sensor layer 13 disposed between the encapsulation layer 18 and the polarizer 20. Touch sensor lines connecting the touch sensor to a touch sensor driver may be formed in the touch sensor layer 13.

[0112] Preferably, the glass substrate 10 has a thin thickness, for example, 200 μm or less, to allow for flexibility and bendability. In the above embodiment, the organic film 12 formed on the glass substrate 10 can be omitted.

[0113] The sidewalls of the edge of the glass substrate 10 can be machined into wedge-shaped sidewalls. The sidewalls at the corners where the two sides of the glass substrate 10 intersect are also machined into wedge-shaped sidewalls. For example... Figure 18 As shown, a wedge shape refers to a shape in which the tapered surface of the upper half of the thickness portion of the glass substrate 10 and the tapered surface of its lower half of the thickness portion are symmetrical about the thickness center REF of the glass substrate 10 when viewed from a cross-section of the edge of the glass substrate 10. Therefore, due to the mutually perpendicular and symmetrical tapered surfaces 10w, the thickness of the glass substrate 10 gradually decreases in the direction from the edge toward the sidewall. The tapered portion of the glass substrate 10 protrudes beyond the circuit layer 14, and the thickness of the glass substrate 10 thins in the direction toward the end of the sidewall of the glass substrate 10.

[0114] Figure 19 This is a diagram illustrating the process steps for manufacturing a wedge-shaped sidewall of a glass substrate according to an embodiment of the present disclosure.

[0115] Reference Figure 19 Multiple display panels 100 can be manufactured simultaneously using multi-panel technology to reduce production costs.

[0116] Simultaneously, a process is performed to form thin films in multiple cells CELL1 to CELL3 on a mother glass 10', which serves as a large glass substrate. Here, a cell is a single unit of the display panel 100. The mother glass 10' is integrally etched to achieve a flexible substrate, and the thickness of the mother glass 10' can be reduced from 500 μm to 200 μm or less. In the multiple cells CELL1 to CELL3 on the mother glass 10', a circuit layer 14 is formed simultaneously, a light-emitting element layer 16 is formed simultaneously, and then an encapsulation layer 18 is formed simultaneously. Subsequently, in a scribing process, the mother glass 10' is cut along scribing line SL by a scribing wheel to separate the mother glass 10' into cell units. After the scribing process, in a finishing process, the contour of each display panel 100 is finished using a laser cutting device.

[0117] As the thickness of the glass substrate 10 decreases, the glass substrate 10 can become more flexible, but the sidewalls at the edges may become rough and uneven, thus cracks can propagate or break due to small impacts. In this disclosure, the edges of the glass substrate 10 of the display panel 100 separated by cell units are etched. In this case, the entire lower surface and sidewalls of the glass substrate 10 may be exposed to the etching solution, or only the sidewalls of the glass substrate 10 may be exposed to the etching solution. Figure 19 As shown, as the etching time increases, a tapered surface 10w begins to form on the edge of the glass substrate 10 exposed to the etching solution, and the tapered surface 10w becomes longer with further increases in etching time. When the lower surface of the glass substrate 10 is exposed to the etching solution during the etching process, the thickness of the glass substrate 10 decreases and the tapered surface 10w becomes longer. The etching process is stopped when the designed thickness and wedge shape of the cross-section of the glass substrate 10 are reached.

[0118] Figure 20 These are illustrations of various examples of wedge-shaped sidewalls on a glass substrate. Figure 21 A cross-sectional photograph of a glass substrate is shown, illustrating the tapered surface when the thickness of the glass substrate is reduced due to the etching process of the glass substrate 10.

[0119] Reference Figure 20 and Figure 21 The wedge-shaped sidewalls of the glass substrate 10 have conical surfaces 10w that are perpendicularly symmetrical to each other based on the thickness center REF of the glass substrate 10. The length L of the conical surface 10w can be determined according to the etching process time. Figure 21 As shown in the photograph, when the lower surface of the glass substrate 10 is exposed to the etching solution during the etching process, the length L of the conical surface 10w can increase as the thickness of the glass substrate 10 decreases. Therefore, the length L of the conical surface 10w can be inversely proportional to the thickness of the glass substrate 10.

[0120] Figure 22This is a block diagram illustrating an example of a display device according to one embodiment of the present disclosure. Figure 23 This is a block diagram illustrating an example of a display device according to another embodiment of the present disclosure. Figure 24A and Figure 24B It is a diagram. Figure 23 The diagram shows an example of a display device being folded. Figure 25 It is a schematic block diagram illustrating the configuration of a driver integrated circuit (IC).

[0121] exist Figure 22 In the display device shown, the display panel 100 can be folded based on the folding portion FO between the first non-folding portion NFO1 and the second non-folding portion NFO2. The first non-folding portion NFO1 includes a pixel array of a screen on which an image is reproduced. The second non-folding portion NFO2 does not include a pixel array. A driver IC 300 can be mounted on the second non-folding portion NFO2, and the second non-folding portion NFO2 can be folded behind the first non-folding portion NFO1.

[0122] exist Figure 23 In the display device shown, the display panel 100 includes a non-folding portion NFO folded based on the folding portion FO. In the display panel 100, the folding portion FO and the non-folding portion NFO may include a pixel array on which an input image is reproduced. Figure 23 In the display device shown, when the flexible display panel 100 is unfolded, the entire screen of the display panel 100 can be activated to display an image on the maximum screen. When the display panel 100 is folded, a portion of the screen can be activated to display an image on an activated area smaller than the maximum screen, and black can be displayed on the inactive area or the previous image can be retained on the inactive area.

[0123] Reference Figures 22 to 25 The display device includes a display panel 100 and a display panel driver, wherein a pixel array is disposed on the screen in the display panel.

[0124] The pixel array of the display panel 100 includes data lines DL, gate lines GL intersecting the data lines DL, and pixels P arranged in a matrix defined by the data lines DL and the gate lines GL. As described in the above embodiment, the structure of the display panel 100 includes a circuit layer and a light-emitting element layer stacked on the glass substrate 10. The light-emitting element layer includes light-emitting elements of the pixel circuitry.

[0125] Figure 23 The display panel 100 shown can be used in Figure 24A The inward folding method shown in the figure or Figure 24BThe display panel 100 is folded in an outward folding manner, as shown in the diagram. In the inward folding manner, the screen displaying the image is the inner surface of the display panel 100 that is folded inward. Therefore, when the display panel 100 is folded in an inward folding manner, the screen is not exposed to the outside. Figure 24B As shown, in the outward folding mode, when the display panel 100 is folded, the display panel 100 is the outer surface exposed to the outside.

[0126] To achieve color, each pixel P includes sub-pixels of different colors. These sub-pixels include red sub-pixels (hereinafter referred to as "R sub-pixels"), green sub-pixels (hereinafter referred to as "G sub-pixels"), and blue sub-pixels (hereinafter referred to as "B sub-pixels"). Although not shown in the accompanying drawings, each pixel P may also include white sub-pixels. Hereinafter, unless otherwise defined, a pixel may be interpreted as a sub-pixel. Each sub-pixel may include pixel circuitry.

[0127] The pixel circuit may include: a light-emitting element; a driving element that provides current to the light-emitting element; a plurality of switching elements for programming the conduction conditions of the driving element and for switching the current path between the driving element and the light-emitting element; and a capacitor for maintaining the gate voltage of the driving element.

[0128] The display panel driver writes pixel data of the input image into pixel P. The display panel driver includes: a data driver 306 that provides data voltage to the data line DL to supply pixel data; and a gate driver 120 that sequentially provides gate pulses to the gate line GL. The data driver 306 can be integrated into the driver IC 300.

[0129] The driver IC 300 can be integrated into the display panel 100. The driver IC 300 receives pixel data and timing signals of the input image from the host system 200, provides the data voltage of the pixel data to the pixels, and synchronizes the data driver 306 with the gate driver 120.

[0130] The driver IC 300 is connected to the data line DL via a data output channel, thereby providing the voltage of the data signal to the data line DL. The driver IC 300 can also output gate timing signals for controlling the gate driver 120 via a gate timing signal output channel. The gate timing signals generated from the timing controller 303 may include a gate start pulse VST and a gate shift clock CLK. The gate start pulse VST and the gate shift clock CLK oscillate between the gate on-voltage VGL and the gate off-voltage VGH. The gate timing signals output from the level shifter 307, such as the gate start pulse VST and the gate shift clock CLK, are applied to the gate driver 120 to control the shift operation of the gate driver 120.

[0131] Gate driver 120 may include a shift register formed together with the pixel array in circuit layer 14 of display panel 100. The shift register of gate driver 120 sequentially provides gate signals to gate lines GL under the control of timing controller 303. Gate signals may include scan pulses and EM pulses of emission signals. The shift register may include a scan driver that outputs scan pulses and an EM driver that outputs EM pulses. Figure 25 In this context, GVST and GCLK refer to the gate timing signals input to the scan driver. EVST and ECLK refer to the gate timing signals input to the EM driver.

[0132] The driver IC 300 can be connected to the host system 200, the first memory 301, and the display panel 100. The driver IC 300 may include a data receiving and computing unit 308, a timing controller 303, a data driver 306, a gamma-compensated voltage generator 305, a power supply 304, and a second memory 302.

[0133] The data receiving and processing unit 308 includes: a receiver for receiving pixel data as a digital signal input from the host system 200; and a data calculator for processing the pixel data input through the receiver to improve image quality. The data calculator may include a data recovery unit for decoding and recovering compressed pixel data and an optical compensator for adding predetermined optical compensation values ​​to the pixel data. The optical compensation value may be set as a value used to correct the brightness of the pixel data based on a measured screen brightness, which is based on camera images captured during the manufacturing process.

[0134] The timing controller 303 provides pixel data of the input image received from the host system 200 to the data driver 306. The timing controller 303 generates gate timing signals for controlling the gate driver 120 and source timing signals for controlling the data driver 306, thereby controlling the operating timing of the gate driver 120 and the data driver 306.

[0135] The data driver 306 converts the pixel data (digital signal) received from the timing controller 303 into a gamma-compensated voltage via a digital-to-analog converter (DAC) to provide the data signal (e.g., Figure 25 The voltages (hereinafter referred to as "data voltages") of DATA1 to DATA6 shown in the figure are used to supply the data voltages output from the data driver 306 to the data lines DL of the pixel array through the output buffer (source amplifier AMP) connected to the data channel of the driver IC 300.

[0136] The gamma compensation voltage generator 305 divides the gamma reference voltage from the power supply 304 using a voltage divider circuit to generate a gamma compensation voltage for each grayscale level. The gamma compensation voltage is an analog voltage that sets the voltage for each grayscale level of the pixel data. The gamma compensation voltage output from the gamma compensation voltage generator 305 is provided to the data driver 306.

[0137] Power supply 304 uses a DC-DC converter to generate the power required to drive the pixel array, gate driver 120, and driver IC 300 of display panel 100. The DC-DC converter may include a charge pump, regulator, buck converter, and boost converter. Power supply 304 can adjust the DC input voltage from host system 200 to generate DC power supplies such as a gamma reference, gate on-state voltage VGL, gate off-state voltage VGH, pixel drive voltage ELVDD, low-level supply voltage ELVSS, and initialization voltage Vini. The gamma reference voltage is provided to gamma compensation voltage generator 305. The gate on-state voltage VGL and gate off-state voltage VGH are provided to level shifter 307 and gate driver 120. Pixel power supplies, such as pixel drive voltage ELVDD, low-level voltage ELVSS, and initialization voltage Vini, are typically provided to pixel P. The initialization voltage Vini is set to a DC voltage lower than the pixel drive voltage ELVDD and the threshold voltage of the OLED light-emitting element to suppress OLED emission.

[0138] When power is supplied to the driver IC 300, the second memory 302 stores compensation values, resistor setting data, etc., received from the first memory 301. The compensation values ​​can be applied to various algorithms to improve image quality. The compensation values ​​may include optical compensation values. The resistor setting data defines the operation of the data driver 306, the timing controller 303, and the gamma compensation voltage generator 305. The first memory 301 may include flash memory. The second memory 302 may include static random access memory (SRAM).

[0139] The host system 200 can be implemented as an application processor (AP). The host system 200 can transmit pixel data of the input image to the driver IC 300 via a Mobile Industry Processor Interface (MIPI). For example, the host system 200 can be connected to the driver IC 300 via a flexible printed circuit (FPC).

[0140] The host system 200 can use sensors to detect Figure 23 The display panel 100 shown is in its folded and unfolded states, and the folding angle is detected.

[0141] In the display device of this disclosure, each of the pixel circuit and the gate driver may include a plurality of transistors. The transistors may be implemented as oxide TFTs including oxide semiconductors, low-temperature polycrystalline silicon (LTPS) TFTs including LTPS, etc. Each transistor may be implemented as a p-channel TFT or an n-channel TFT. In this embodiment, the transistors of the pixel circuit are mainly described using an example implemented as a p-channel TFT, but this disclosure is not limited thereto.

[0142] A transistor is a three-electrode device comprising a gate, a source, and a drain. The source is the electrode that supplies charge carriers to the transistor. In a transistor, charge carriers begin to flow from the source. The drain is the electrode from which charge carriers are released from the transistor to the outside. In a transistor, charge carriers flow from the source to the drain. In the case of an n-channel transistor, since the charge carriers are electrons, the source voltage is lower than the drain voltage to allow electrons to flow from the source to the drain. In an n-channel transistor, current flows from the drain to the source. In the case of a p-channel transistor (p-type metal-oxide-semiconductor (PMOS)), since the charge carriers are holes, the source voltage is higher than the drain voltage to allow holes to flow from the source to the drain. In a p-channel transistor, current flows from the source to the drain because holes flow from the source to the drain. It should be noted that the source and drain of a transistor are not fixed. For example, the source and drain can change depending on the applied voltage. Therefore, this disclosure is not limited to the source and drain of a transistor. In the following description, the source and drain of the transistor will be referred to as the first electrode and the second electrode, respectively.

[0143] The gate pulse oscillates between the gate on-voltage and the gate off-voltage. The gate on-voltage is set to a voltage higher than the transistor's threshold voltage, and the gate off-voltage is set to a voltage lower than the transistor's threshold voltage. The transistor turns on in response to the gate on-voltage and turns off in response to the gate off-voltage. In the case of an n-channel transistor, the gate on-voltage can be the gate high voltage VGH, and the gate off-voltage can be the gate low voltage VGL. In the case of a p-channel transistor, the gate on-voltage can be the gate low voltage VGL, and the gate off-voltage can be the gate high voltage VGH.

[0144] The driving element for each pixel can be implemented as a transistor. The driving element should have uniform electrical characteristics across all pixels. However, due to process variations and component characteristic variations, differences may exist between pixels, and the electrical characteristics may change over time as the display operates. To compensate for these variations in driving element electrical characteristics, the display device may include internal and external compensation circuitry. Internal compensation circuitry is added to the pixel circuitry in each sub-pixel to sample the threshold voltage Vth and / or mobility μ of the driving element, which vary according to its electrical characteristics, and to compensate for these variations in real time. External compensation circuitry transmits the threshold voltage Vth and / or mobility μ of the driving element, detected via a sensing line connected to the sub-pixel, to an external compensator. The compensator in the external compensation circuitry compensates for the variations in the driving element electrical characteristics by reflecting the detection results and modulating the pixel data of the input image. The external compensation circuitry senses the voltage of the pixel, which varies according to the driving element electrical characteristics, and modulates the data of the input image in external circuitry based on the detected voltage, thereby compensating for the variations in driving element electrical characteristics between pixels.

[0145] Figure 26 This is a circuit diagram illustrating an example of a pixel circuit. Figure 27 It is a diagram Figure 26 A diagram illustrating a driving method for a pixel circuit is shown. Pixel circuits applicable to this disclosure are not limited to... Figure 26 and Figure 27 The pixel circuit shown in the figure.

[0146] Reference Figure 26 and Figure 27 The pixel circuit includes: an OLED light-emitting element; a driving element DT that provides current to the OLED; and an internal compensation circuit that samples the threshold voltage Vth of the driving element DT using multiple switching elements M1 to M6, thereby compensating the gate voltage of the driving element DT for a voltage as large as the threshold voltage Vth. Each of the driving element DT and the switching elements M1 to M6 can be implemented as a p-channel TFT.

[0147] The driving period of a pixel circuit using an internal compensation circuit can be divided into the initialization period Tini, the sampling period Tsam, the data writing period Twr, and the emission period Tem.

[0148] During the initialization period Tini, the (N-1)th scan signal SCAN(N-1) is generated as the gate on-state voltage VGL, and the voltage of each of the Nth scan signal SCAN(N) and the light-emitting signal EM(N) is the gate off-state voltage VGH. During the sampling period Tsam, the Nth scan signal SCAN(N) is generated as a pulse of the gate on-state voltage VGL, and the voltage of each of the (N-1)th scan signal SCAN(N-1) and the light-emitting signal EM(N) becomes the gate off-state voltage VGH. During the data writing period Twr, the voltage of each of the (N-1)th scan signal SCAN(N-1), the Nth scan signal SCAN(N), and the light-emitting signal EM(N) becomes the gate off-state voltage VGH. During at least a portion of the light-emitting period Tem, the light-emitting signal EM(N) is generated as the gate on-state voltage VGL, and the voltage of each of the (N-1)th scan signal SCAN(N-1) and the Nth scan signal SCAN(N) is generated as the gate off-state voltage VGH.

[0149] During the initialization period Tini, the fifth switching element M5 and the sixth switching element M6 are turned on according to the gate on-state voltage VGL of the (N-1)th scan signal SCAN(N-1), thereby initializing the pixel circuit. During the sampling period Tsam, the first switching element M1 and the second switching element M2 are turned on according to the gate on-state voltage VGL of the Nth scan signal SCAN(N), sampling the threshold voltage of the driving element DT to charge the capacitor Cst. During the data writing period Twr, the first switching element M1 to the sixth switching element M6 remain in the off state. During the emission period Tem, the third switching element M3 and the fourth switching element M4 are turned on, causing the OLED to emit light. During the emission period Tem, in order to accurately represent the brightness of low gray levels with the duty cycle of the emission signal EM(N), the emission signal EM(N) can swing between the gate on-state voltage VGL and the gate off-state voltage VGH with a predetermined duty cycle to repeatedly turn the third switching element M3 and the fourth switching element M4 on / off.

[0150] OLEDs can be implemented as organic light-emitting diodes or inorganic light-emitting diodes. The following describes an example of an OLED implemented as an organic light-emitting diode.

[0151] An OLED (Optical Display Cell) may include an organic compound layer formed between an anode and a cathode. The organic compound layer may include a hole injection layer (HIL), a hole transport layer (HTL), an emissive layer (EML), an electron transport layer (ETL), and an electron injection layer (EIL), but this disclosure is not limited thereto. When a voltage is applied to the anode and cathode of the OLED, holes passing through the hole transport layer (HTL) and electrons passing through the electron transport layer (ETL) move to the emissive layer (EML) to form excitons, thereby emitting visible light from the emissive layer (EML).

[0152] The anode of the OLED is connected to a fourth node n4 between the fourth switching element M4 and the sixth switching element M6. The fourth node n4 is connected to the anode of the OLED, the second electrode of the fourth switching element M4, and the second electrode of the sixth switching element M6. The cathode of the OLED is connected to the VSS line PL3, to which a low-potential power supply voltage ELVSS is applied. The OLED emits light using a current Ids flowing according to the gate-source voltage Vgs of the driving element DT. The current path of the OLED is switched through the third switching element M3 and the fourth switching element M4.

[0153] Storage capacitor Cst is connected to VDD line PL1 and second node n2. Data voltage Vdata, which compensates for a voltage as large as the threshold voltage Vth of the driving element DT, is charged into storage capacitor Cst. Since the data voltage Vdata in each sub-pixel compensates for a voltage as large as the threshold voltage Vth of the driving element DT, it compensates for the characteristic deviation of the driving element DT in each sub-pixel.

[0154] The first switching element M1 is turned on in response to the gate turn-on voltage VGL of the Nth scan pulse SCAN(N) to connect the second node n2 to the third node n3. The second node n2 is connected to the gate of the driving element DT, the first electrode of the storage capacitor Cst, and the first electrode of the first switching element M1. The third node n3 is connected to the second electrode of the driving element DT, the second electrode of the first switching element M1, and the first electrode of the fourth switching element M4. The gate of the first switching element M1 is connected to the first gate line GL1 to receive the Nth scan pulse SCAN(N). The first electrode of the first switching element M1 is connected to the second node n2, and the second electrode of the first switching element M1 is connected to the third node n3.

[0155] The second switching element M2 is turned on in response to the gate turn-on voltage VGL of the Nth scan pulse SCAN(N) to provide the data voltage Vdata to the first node n1. The gate of the second switching element M2 is connected to the first gate line GL1 to receive the Nth scan pulse SCAN(N). The first electrode of the second switching element M2 is connected to the first node n1. The second electrode of the second switching element M2 is connected to the data line DL to which the data voltage Vdata is applied. The first node n1 is connected to the first electrode of the second switching element M2, the second electrode of the third switching element M3, and the first electrode of the driving element DT.

[0156] The third switching element M3 is turned on in response to the gate turn-on voltage VGL of the light-emitting signal EM(N) to connect the VDD line PL1 to the first node n1. The gate of the third switching element M3 is connected to the third gate line GL3 to receive the light-emitting signal EM(N). The first electrode of the third switching element M3 is connected to the VDD line PL1. The second electrode of the third switching element M3 is connected to the first node n1.

[0157] The fourth switching element M4 is turned on in response to the gate turn-on voltage VGL of the light-emitting signal EM(N) to connect the third node n3 to the anode of the light-emitting element OLED. The gate of the fourth switching element M4 is connected to the third gate line GL3 to receive the light-emitting signal EM(N). The first electrode of the fourth switching element M4 is connected to the third node n3, and the second electrode of the fourth switching element M4 is connected to the fourth node n4.

[0158] The fifth switching element M5 is turned on in response to the gate turn-on voltage VGL of the (N-1)th scan pulse SCAN(N-1) to connect the second node n2 to the Vini line PL2. The gate of the fifth switching element M5 is connected to the second gate line GL2 to receive the (N-1)th scan pulse SCAN(N-1). The first electrode of the fifth switching element M5 is connected to the second node n2, and the second electrode of the fifth switching element M5 is connected to the Vini line PL2.

[0159] The sixth switching element M6 is turned on in response to the gate turn-on voltage VGL of the (N-1)th scan pulse SCAN(N-1) to connect the Vini line PL2 to the fourth node n4. The gate of the sixth switching element M6 is connected to the second gate line GL2 to receive the (N-1)th scan pulse SCAN(N-1). The first electrode of the sixth switching element M6 is connected to the Vini line PL2, and the second electrode of the sixth switching element M6 is connected to the fourth node n4.

[0160] The driving element DT controls the current Ids flowing in the light-emitting element OLED according to the gate-source voltage Vgs, thereby driving the light-emitting element OLED. The driving element DT includes a gate connected to the second node n2, a first electrode connected to the first node n1, and a second electrode connected to the third node n3.

[0161] During the initialization period Tini, the (N-1)th scan signal SCAN(N-1) is generated as the gate turn-on voltage VGL. During the initialization period Tini, the Nth scan signal SCAN(N) and the emission signal EM(N) are held at the gate cut-off voltage VGH. Therefore, during the initialization period Tini, the fifth switching element M5 and the sixth switching element M6 are turned on, thereby initializing the second node n2 and the fourth node n4 to the initialization voltage Vini. A hold period Th can be set between the initialization period Tini and the sampling period Tsam. During the hold period Th, the voltages of SCAN(N-1), SCAN(N), and EM(N) are the gate cut-off voltage VGH.

[0162] During the sampling period Tsam, the Nth scan pulse SCAN(N) is generated as the gate on-voltage VGL. The pulse of the Nth scan pulse SCAN(N) is synchronized with the data voltage Vdata of the Nth pixel row. During the sampling period Tsam, each of the (N-1)th scan pulse SCAN(N-1) and the light emission signal EM(N) is maintained at the gate off-voltage VGH. Therefore, during the sampling period Tsam, the first switching element M1 and the second switching element M2 are turned on.

[0163] During the sampling period Tsam, the gate voltage DTG of the driving element DT rises due to the current flowing through the first switching element M1 and the second switching element M2. Since the driving element DT is off, the gate voltage DTG is Vdata - |Vth|. In this case, the voltage at the third node n3 is also Vdata - |Vth|. During the sampling period Tsam, the gate-source voltage Vgs of the driving element DT is |Vgs| = Vdata - (Vdata - |Vth|) = |Vth|.

[0164] During the data write period Twr, the Nth scan pulse SCAN(N) is inverted to the gate cutoff voltage VGH. During the data write period Twr, each of the (N-1)th scan pulse SCAN(N-1) and the light emission signal EM(N) is maintained at the gate cutoff voltage VGH. Therefore, during the data write period Twr, all switching elements M1 to M6 remain in the off state.

[0165] During the emission period Tem, an emission signal EM(N) can be generated as the gate cutoff voltage VGH. During the emission period Tem, to improve low grayscale performance, the emission signal EM(N) can be turned on or off with a predetermined duty cycle, thereby oscillating between the gate on-state voltage VGL and the gate off-state voltage VGH. Therefore, during at least a portion of the emission period Tem, an emission signal EM(N) can be generated as the gate on-state voltage VGL.

[0166] When the emission signal EM(N) is the gate on-state voltage VGL, current flows between ELVDD and the OLED, allowing the OLED to emit light. During the emission period Tem, the (N-1)th scan pulse SCAN(N-1) and the Nth scan pulse SCAN(N) are held at the gate off-state voltage VGH. During the emission period Tem, the third switching element M3 and the fourth switching element M4 are repeatedly turned on and off according to the voltage of the emission signal EM(N). When the emission signal EM(N) is the gate on-state voltage VGL, the third switching element M3 and the fourth switching element M4 are turned on, allowing current to flow in the OLED. In this case, the gate-source voltage Vgs of the driving element DT becomes the voltage |Vgs| = VDD - (Vdata - |Vth|), and the current flowing in the OLED is the current K(VDD - Vdata). 2 K is a constant value determined by charge mobility, parasitic capacitance, and channel capacitance of the driving element DT.

[0167] Figure 28 This is a detailed cross-sectional view illustrating the cross-sectional structure of a display panel 100 according to one embodiment of the present disclosure. It should be noted that... Figure 28 The cross-sectional structure of the display panel 100 shown is merely an example, and the content of this disclosure is not limited thereto.

[0168] Reference Figure 28 As mentioned above, the circuit layer, the light-emitting element layer, and the encapsulation layer can be stacked on the glass substrate (GLS).

[0169] A first buffer layer BUF1 can be formed on a glass substrate (GLS). A first metal layer LS can be formed on the first buffer layer BUF1, and a second buffer layer BUF2 can be formed on the first metal layer LS. Each of the first buffer layer BUF1 and the second buffer layer BUF2 can be made of an inorganic insulating material and can be formed from one or more insulating layers. The first metal layer LS may include a metal pattern disposed below the TFT to block light emitted to the semiconductor channel layer of the TFT.

[0170] An active layer ACT can be formed on the second buffer layer BUF2. The active layer ACT includes semiconductor patterns for each of the TFTs in the pixel circuit and the TFTs in the gate driver. When the TFTs are implemented as oxide TFTs, the semiconductor patterns may include indium gallium zinc oxide (IGZO).

[0171] A gate insulating layer GI can be formed on the active layer ACT. The gate insulating layer GI is an insulating layer made of inorganic insulating material. A second metal layer GATE can be formed on the gate insulating layer GI. The second metal layer GATE may include the gate electrode of the TFT and the gate line connected to the gate electrode.

[0172] The first interlayer insulating layer ILD1 may cover the second metal layer GATE. A third metal layer TM may be formed on the first interlayer insulating layer ILD1, and the second interlayer insulating layer ILD2 may cover the third metal layer TM. The capacitor Cst of the pixel circuit may be formed in the overlapping portion of the second metal layer GATE, the first interlayer insulating layer ILD1, and the third metal layer TM. The first interlayer insulating layer ILD1 and the second interlayer insulating layer ILD2 may each comprise an inorganic insulating material.

[0173] A fourth metal layer SD1 can be formed on the second interlayer insulating layer ILD2. An inorganic insulating layer PAS1 and a first planarization layer PLN1 can be stacked on the fourth metal layer SD1. A fifth metal layer SD2 can be formed on the first planarization layer PLN1. A portion of the pattern of the fifth metal layer SD2 can be connected to the fourth metal layer SD1 through contact holes passing through the first planarization layer PLN1 and the inorganic insulating layer PAS1. The first planarization layer PLN1 and the second planarization layer PLN2 can each be made of an organic insulating material whose surface is planarized.

[0174] The fourth metal layer SD1 may include a first electrode and a second electrode of the TFT, which are connected to the semiconductor pattern of the TFT through contact holes passing through the second interlayer insulating layer ILD2. Data lines DL and power lines PL1 and PL2 can be implemented by patterning the fourth metal layer SD1 or the fifth metal layer SD2.

[0175] An anode electrode AND for an OLED light-emitting element can be formed on the second planarization layer PLN2. The anode electrode AND can be connected to the electrode of a TFT used as a switching element or driving element through a contact hole in the second planarization layer PLN2. The anode electrode AND can be made of a transparent or translucent electrode material.

[0176] The pixel defining layer (BNK) can cover the anode electrode (AND) of the OLED light-emitting element. The BNK is patterned to define light-emitting regions (or opening regions), through which light passes from each pixel to the outside. Spacer structures (SPCs) can be formed on the BNK. The BNK and SPCs can be integrated using the same organic insulating material. The SPCs ensure a gap between the fine metal mask (FMM) and the anode electrode (AND) to prevent the FMM from contacting the anode electrode (AND) during the deposition process of the organic compound EL.

[0177] Organic compound EL is formed in the light-emitting region of each pixel defined by the pixel defining layer BNK. A cathode electrode CAT for the light-emitting element OLED is formed on the entire surface of the display panel 100, covering the pixel defining layer BNK, the spacer SPC, and the organic compound EL. The cathode electrode CAT can be connected to a VSS line PL3 formed from any of the metal layers beneath the cathode electrode CAT. A capping layer CPL can cover the cathode electrode CAT. The capping layer CPL is formed of an inorganic insulating material, and it protects the cathode electrode CAT by preventing air infiltration and degassing of the organic insulating material applied to the capping layer CPL. An inorganic insulating layer PAS2 can cover the capping layer CPL, and a planarization layer PCL can be formed on the inorganic insulating layer PAS2. The planarization layer PCL may include an organic insulating material. An inorganic insulating layer PAS3, which forms an encapsulation layer, can be formed on the planarization layer PCL.

[0178] According to this disclosure, a flexible display panel is manufactured based on a glass substrate, and a residual glass film or glass pattern is added to the folded portion of the flexible display panel to increase the rigidity of the folded portion.

[0179] According to this disclosure, the manufacturing process of flexible display panels does not require the separation of the polyimide (PI) film substrate from the carrier substrate. Therefore, according to this disclosure, expensive laser equipment is not required, defects caused by the peeling process of the PI film substrate from the carrier substrate can be prevented, and the rigidity of the folded portion of the flexible display panel can be increased to prevent creases or hinge marks.

[0180] Furthermore, according to this disclosure, by adding beads of organic material to the folded portion of the flexible display panel, the rigidity of the folded portion can be further increased, and beads made of quantum dot (QD) material can be used to improve the color reproduction and viewing angle of the folded portion.

[0181] Furthermore, according to this disclosure, since the circuit layer can be mounted on the glass substrate by removing the PI film substrate, not only can wrinkles in the folded portion be prevented, but the durability of the flexible display panel can also be enhanced and the manufacturing cost reduced.

[0182] The effects achievable by this disclosure are not limited to those described above. That is, those skilled in the art to which this disclosure pertains will readily understand from the following description other purposes not mentioned.

[0183] It will be apparent to those skilled in the art that various modifications can be made to the exemplary embodiments of this disclosure without departing from the spirit or scope thereof. Therefore, this disclosure is intended to cover all such modifications, provided they fall within the scope of the appended claims and their equivalents.

[0184] It should be noted that the embodiments of this disclosure can be used individually or in combination.

[0185] The flexible display panel according to various embodiments of this disclosure can be described as follows.

[0186] Embodiment 1: A flexible display panel includes: a glass substrate 10; a circuit layer 14 disposed on the glass substrate 10 and configured to drive pixels; a light-emitting element layer 16 disposed on the circuit layer 14; an encapsulation layer 18 covering the circuit layer 14 and the light-emitting element layer 16; a polarizing plate 20 disposed on the encapsulation layer 18; and a cover glass disposed on the polarizing plate 20, such as... Figure 5 , 7 As shown in 11, 12, etc.

[0187] At least one of the glass substrate and the cover glass includes a buffer portion.

[0188] The buffer section includes an organic filler 30 and a glass 40. The glass 40 of the buffer section has a thickness less than or equal to the thickness of the glass substrate and includes a pattern of a specific shape.

[0189] Implementation method 2: The buffer section also includes beads disposed in the organic filler, such as... Figure 11 As shown in the image.

[0190] Implementation method 3: The buffer section also includes quantum dot (QD) material disposed in the organic filler, such as... Figure 11 As shown in the image.

[0191] Embodiment 4: The cover glass also includes beads disposed in the folded area overlapping the buffer portion of the glass substrate, such as... Figure 12 As shown in the image.

[0192] Implementation method 5: The beads include quantum dot (QD) materials.

[0193] Embodiment 6: The flexible display panel according to Embodiment 1 further includes a bead film, which is disposed between the polarizing plate and the cover glass, and beads are dispersed in the bead film, such as... Figure 13 As shown in the image.

[0194] Implementation method 7: The beads are only disposed in the folded area that overlaps with the buffer portion of the glass substrate.

[0195] Implementation method 8: The beads include quantum dot (QD) materials, such as... Figure 13 and 14 As shown in the image.

[0196] Implementation Method 9: One or more buffer portions are provided in the bendable folding area of ​​the flexible display panel, such as... Figure 15A , Figure 15B , Figure 16A , Figure 16B As shown in the diagram. In the folded region, the thickness of the glass in the portion with greater curvature differs from the thickness of the glass in the portion with relatively smaller curvature.

[0197] Implementation Method 10: The ratio of the thickness of the organic filler to the thickness of the glass in the buffer section is in the range of 6 to 10:4 to 9, such as... Figure 5 , Figure 7 , Figure 11 and Figure 12 As shown in the image.

[0198] Implementation method 11: The ratio of the thickness of the organic filler in the buffer section to the thickness of the glass is 6:4.

[0199] Embodiment 12: The sidewalls of the glass substrate edge include vertically symmetrical wedge-shaped conical surfaces, and the thickness of the sidewalls decreases in the direction toward the ends of the sidewalls, such as... Figure 17 and Figure 18 As shown in the image.

[0200] Implementation method 13: The tapered surface protrudes beyond the circuit layer.

[0201] Implementation method 14: The length of the conical surface is inversely proportional to the thickness of the glass substrate.

[0202] Embodiment 15: A flexible display panel includes: a glass substrate 10; a circuit layer 14 disposed on the glass substrate 10 and configured to drive pixels; a light-emitting element layer 16 disposed on the circuit layer 14; an encapsulation layer 18 covering the circuit layer 14 and the light-emitting element layer 16; a polarizing plate 20 disposed on the encapsulation layer 18; and a cover glass 22 disposed on the polarizing plate 20.

[0203] At least one of the glass substrate and the cover glass includes a buffer portion. The buffer portion includes an organic filler and glass. The ratio of the thickness of the organic filler to the thickness of the glass in the buffer portion is in the range of 6 to 10:4 to 9.

[0204] Implementation 16: The light-emitting element layer includes an organic light-emitting diode (OLED). The circuit layer includes transistors configured to provide current to the organic light-emitting diode.

[0205] Implementation method 17: The flexible display panel is foldable based on the folding area where the buffer is located.

[0206] The purpose of this disclosure, the means to achieve these purposes, and the effects of the aforementioned disclosure do not specify the essential features of the claims. Therefore, the scope of the claims is not limited to the disclosure of this disclosure.

[0207] Although embodiments of the present disclosure have been described in more detail with reference to the accompanying drawings, the present disclosure is not limited thereto and may be implemented in many different forms without departing from the technical concept of the present disclosure. Therefore, the embodiments disclosed in this disclosure are provided for illustrative purposes only and are not intended to limit the technical concept of the present disclosure. The scope of the technical concept of the present disclosure is not limited thereto. Therefore, it should be understood that the above embodiments are illustrative in all respects and do not limit the present disclosure. The scope of protection of the present disclosure should be interpreted based on the appended claims, and all technical concepts within the scope of their equivalents should be interpreted as falling within the scope of the present disclosure.

Claims

1. A flexible display panel, comprising: Glass substrate; A circuit layer disposed on the glass substrate and configured to drive pixels; A light-emitting element layer disposed on the circuit layer; An encapsulation layer covering the circuit layer and the light-emitting element layer; A touch sensor layer disposed on the encapsulation layer; A polarizing plate disposed on the touch sensor layer; as well as The cover glass disposed on the polarizing plate, At least one of the glass substrate and the cover glass includes a buffer portion. The buffer section includes organic filler and glass. The glass in the buffer portion has a thickness less than or equal to the thickness of the glass substrate, and The sidewalls of the edge of the glass substrate include vertically symmetrical wedge-shaped conical surfaces, and the thickness of the sidewalls decreases in the direction toward the end of the sidewalls.

2. The flexible display panel according to claim 1, wherein the buffer portion further comprises quantum dot (QD) material disposed in the organic filler.

3. The flexible display panel according to claim 2, wherein the buffer portion further comprises beads disposed in the organic filler. The beads mentioned therein comprise the quantum dot (QD) material.

4. The flexible display panel according to claim 2, wherein the cover glass further comprises beads disposed in a folded region overlapping the buffer portion of the glass substrate.

5. The flexible display panel according to claim 4, wherein the beads comprise the quantum dot (QD) material.

6. The flexible display panel according to claim 1, wherein: One or more of the aforementioned buffer portions are provided in the bendable folding area of ​​the flexible display panel; and In the folded region, the thickness of the glass in the portion with greater curvature is different from the thickness of the glass in the portion with relatively smaller curvature.

7. The flexible display panel according to claim 1, wherein the ratio of the thickness of the organic filler in the buffer portion to the thickness of the glass is in the range of 6 to 10: 4 to 9.

8. The flexible display panel according to claim 7, wherein the ratio of the thickness of the organic filler in the buffer portion to the thickness of the glass is 6:

4.

9. The flexible display panel of claim 1, wherein the tapered surface protrudes beyond the circuit layer.

10. The flexible display panel according to claim 1, wherein the length of the tapered surface is inversely proportional to the thickness of the glass substrate.

11. A flexible display panel, comprising: Glass substrate; A circuit layer disposed on the glass substrate and configured to drive pixels; A light-emitting element layer disposed on the circuit layer; An encapsulation layer covering the circuit layer and the light-emitting element layer; A touch sensor layer disposed on the encapsulation layer; A polarizing plate disposed on the touch sensor layer; Covering glass disposed on the polarizing plate; as well as A beaded film is disposed between the polarizing plate and the cover glass, and beads are dispersed in the beaded film. At least one of the glass substrate and the cover glass includes a buffer portion. The buffer section comprises organic filler and glass, and The beads described herein comprise quantum dot (QD) materials, and The beads are disposed only in the folded area that overlaps with the buffer portion of the glass substrate.

12. A flexible display panel, comprising: Glass substrate; A circuit layer disposed on the glass substrate and configured to drive pixels; A light-emitting element layer disposed on the circuit layer; An encapsulation layer covering the circuit layer and the light-emitting element layer; A touch sensor layer disposed on the encapsulation layer; A polarizing plate disposed on the touch sensor layer; as well as The cover glass disposed on the polarizing plate, At least one of the glass substrate and the cover glass includes a buffer portion. The buffer section includes organic filler and glass. The glass in the buffer portion has a thickness less than or equal to the thickness of the glass substrate. The buffer section further includes beads disposed in the organic filler, and The beads mentioned therein comprise quantum dot (QD) materials.

13. A flexible display panel, comprising: Glass substrate; A circuit layer disposed on the glass substrate and configured to drive pixels; A light-emitting element layer disposed on the circuit layer; An encapsulation layer covering the circuit layer and the light-emitting element layer; A touch sensor layer disposed on the encapsulation layer; A polarizing plate disposed on the touch sensor layer; as well as The cover glass disposed on the polarizing plate, At least one of the glass substrate and the cover glass includes a buffer portion. The buffer section includes organic filler and glass. The ratio of the thickness of the organic filler in the buffer section to the thickness of the glass is in the range of 6 to 10:4 to 9. The buffer portion is disposed in the bendable folding area of ​​the flexible display panel, and includes a first buffer portion and a second buffer portion. In each of the first and second buffer portions, the organic filler fills the pores and the glass overlaps with the organic filler and the pores. The first buffer portion is the one located in the portion with the maximum curvature when the folded region is bent. The thickness of the glass in the first buffer section is different from the thickness of the glass in the second buffer section.

14. The flexible display panel according to any one of claims 1 to 13, wherein: The light-emitting element layer includes an organic light-emitting diode (OLED); and The circuit layer includes transistors configured to provide current to the organic light-emitting diode.

15. The flexible display panel according to any one of claims 1 to 13, wherein the flexible display panel is foldable based on the folding area where the buffer portion is located.

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