Flexible display device

Abstract

A flexible display device is provided, including a flexible substrate including a bending area, an insulating layer formed on the flexible substrate and including at least one cut formed to correspond to the bending area, and a plurality of wirings formed along a surface shape of the insulating layer in the bending area. The at least one cut can include an inclined sidewall, and a width of the inclined sidewall can be equal to or greater than a depth of the cut.

Description

[0001] This application is a divisional application of patent application No. 201610625717.4, filed on August 2, 2016, entitled "Flexible Display Device". Technical Field

[0002] The technology described generally relates to a flexible display device with a curved region. Background Technology

[0003] Unlike LCDs, OLEDs, being self-emissive, do not require a separate light source, allowing for relatively small thickness and weight. Furthermore, OLEDs exhibit high-quality characteristics such as low power consumption, high brightness, and fast response times.

[0004] A typical organic light-emitting diode (OLED) display includes: a substrate; thin-film transistors (TFTs) formed on the substrate; an OLED that emits light controlled by the TFTs; and multiple insulating layers disposed between the electrodes forming the TFTs. Recently, flexible OLED displays incorporating flexible substrates with curved regions formed therein have been developed.

[0005] The information disclosed in this background section is only intended to enhance the understanding of the background of the described technology. Therefore, the above information may contain information that does not constitute prior art known to a person skilled in the art in this country. Summary of the Invention

[0006] The described technology has been dedicated to providing a flexible display device and a method thereof that can effectively prevent cracks in the insulation layer and short circuits between wirings caused by bending of the flexible display device.

[0007] One embodiment provides a flexible display device, the flexible display device comprising: a flexible substrate including a curved region; an insulating layer formed on the flexible substrate and including at least one cut corresponding to the curved region; and a plurality of wirings formed along the surface shape of the insulating layer in the curved region. The at least one cut may include inclined sidewalls, the width of which may be equal to or greater than the depth of the cut.

[0008] The inclined sidewalls may have a convex shape facing the flexible substrate. The inclined sidewalls may include a first sidewall and a second sidewall spaced apart from each other, and the bottom surface of the at least one cut may be disposed between the first sidewall and the second sidewall. The plurality of wirings may be formed along the top surface, the first sidewall, the bottom surface, and the second sidewall of the insulating layer.

[0009] Multiple cuts can be formed, and these cuts can be spaced apart from each other along the length of multiple wirings. The curved region can be curved based on a bending axis, and the at least one cut can be formed extending in a direction parallel to the bending axis. The at least one cut can be formed by isotropic etching using an etching paste.

[0010] The flexible substrate may include a display area and a non-display area, and the curved area may be included in the non-display area. The flexible display device may also include display units formed in the display area on the flexible substrate.

[0011] Multiple wirings can be electrically connected to multiple signal lines included in the display unit.

[0012] The flexible display device may also include a driver integrated circuit formed in the non-display area and electrically connected to multiple wirings, and multiple pad electrodes. The driver integrated circuit and multiple pad electrodes can be stacked with the display unit on the rear side of the display unit through a bending region.

[0013] The insulating layer may include multiple inorganic layers, and the at least one cutout may be formed in at least one of the topmost layers comprising the multiple inorganic layers. The insulating layer and multiple wirings in the non-display area may be covered by a passivation layer comprising an organic material.

[0014] Another embodiment provides a flexible display device, the flexible display device comprising: a display area in which display units are formed; a curved region on one side of the display area; and a data driver region on one side of the curved region and superimposed on the display area. An insulating layer including slits and multiple wirings formed along the surface shape of the insulating layer may be disposed in the curved region. The slits may include inclined sidewalls, the width of which may be equal to or greater than the depth of the slits.

[0015] The curved area can be curved based on the bending axis, the cut can be formed extending in a direction parallel to the bending axis, and the sidewall can have a downward convex shape.

[0016] Another embodiment provides a method for manufacturing a flexible display device, comprising: forming an insulating layer on a flexible substrate; forming cuts in the insulating layer using an etch paste; forming a plurality of wirings along the surface shape of the insulating layer in which the cuts are formed; and forming a curved region by bending a portion of the flexible substrate in which the cuts are formed.

[0017] Cuts can be formed by isotropic etching with an etching paste, and the depth of the cuts can be controlled by adjusting the etching time of the etching paste.

[0018] The cut may include inclined sidewalls, the width of which is equal to or greater than the depth of the cut. The sidewalls may have a convex shape facing the flexible substrate. The curved region may be curved based on a bending axis, and the cut may be formed extending in a direction parallel to the bending axis.

[0019] According to various embodiments, it is possible to effectively prevent cracks in the insulation layer and short circuits between wirings due to bending of the flexible display device. Attached Figure Description

[0020] Figure 1 A schematic perspective view of a flexible display device according to an embodiment is shown.

[0021] Figure 2 A schematic cross-sectional view of a flexible display device according to an embodiment is shown.

[0022] Figure 3 It is shown Figure 1 The diagram shows a schematic perspective view of the flexible display device in its folded state.

[0023] Figure 4 It is shown Figure 2 The diagram shows a schematic cross-sectional view of the flexible display device in its folded state.

[0024] Figure 5A A partial top view of the non-display area of ​​a flexible display device according to a comparative example is shown.

[0025] Figure 5B Showing the VV intercept along the line Figure 5A A schematic cross-sectional view of a flexible display device.

[0026] Figure 5C This is a schematic cross-sectional view showing the curved area of ​​a flexible display device according to a comparative example.

[0027] Figure 6A A partial top view of the non-display area of ​​a flexible display device according to an embodiment is shown.

[0028] Figure 6B Showing the section intercepted along line VI-VI Figure 6A A schematic cross-sectional view of a flexible display device.

[0029] Figure 7 A schematic cross-sectional view of a flexible display device according to another embodiment is shown.

[0030] Figure 8 Show Figure 1 The equivalent circuit diagram of a pixel is shown in the figure.

[0031] Figure 9 Show Figure 1The image shows an enlarged cross-sectional view of the display unit and the non-display area.

[0032] Figure 10 A process flow diagram illustrating a method for manufacturing a flexible display device according to an embodiment is shown.

[0033] Figure 11A Show Figure 10 The diagram shows a schematic cross-sectional view of the flexible display device in the first step.

[0034] Figure 11B Show Figure 10 The diagram shows a schematic cross-sectional view of the flexible display device in the second step.

[0035] Figure 11C Show Figure 10 The diagram shows a schematic cross-sectional view of the flexible display device in the third step.

[0036] Figure 11D Show Figure 10 The diagram shows a schematic cross-sectional view of the flexible display device in the fourth step. Detailed Implementation

[0037] The present disclosure will now be described more fully with reference to the accompanying drawings, which illustrate specific embodiments thereof. As those skilled in the art will recognize, the described embodiments may be modified in various ways without departing from the spirit or scope of the present disclosure.

[0038] Throughout this specification, it will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, the element may be directly on said other element or there may be an intermediate element present. Furthermore, the phrase "on" means located on or below a portion of the object, and does not necessarily mean located on the upper side of the object based on the direction of gravity.

[0039] Throughout this specification, unless explicitly stated otherwise, the word "comprising" shall be understood to imply the inclusion of the stated elements, but not to exclude any other elements. In the accompanying drawings, dimensions and thicknesses of individual elements are shown arbitrarily for ease of description, and this disclosure is not necessarily limited to the dimensions and thicknesses shown.

[0040] Figure 1 and Figure 2 A schematic perspective view and a schematic cross-sectional view of a flexible display device according to an embodiment are shown respectively. Figure 3 and Figure 4 Each is shown separately. Figure 1 and Figure 2 The diagram shows a schematic perspective view and a schematic cross-sectional view of the corresponding flexible display device in its folded state.

[0041] Reference Figures 1 to 4 The flexible display device 100 of the embodiment includes a flexible substrate 110, a display unit 120 formed on the flexible substrate 110, an insulating layer 130, and multiple wirings 140. In addition, the flexible display device 100 includes an external driver 150 such as a printed circuit board (PCB).

[0042] The flexible substrate 110 may include an organic material, including at least one selected from polyimide, polycarbonate, polyethylene, polyethylene terephthalate, and polyacrylate. The flexible substrate 110 may be light-transmitting and bendable by external force. The flexible substrate 110 includes a display area (DA) in which the display unit 120 is formed and a non-display area (NDA) formed outside the display area (DA).

[0043] The display unit 120 includes a plurality of pixels PX and displays an image by combining the light emitted from the plurality of pixels PX. Each pixel PX includes pixel circuitry and an organic light-emitting diode (OLED). The pixel circuitry includes at least two thin-film transistors and at least one storage capacitor, and controls the light emission of the OLED. The detailed structure of the display unit 120 is described below.

[0044] Multiple pad electrodes 160 and multiple wirings 140 are formed in the non-display area (NDA) of the flexible substrate 110. The multiple pad electrodes 160 are formed on the edge of the flexible substrate 110, and the multiple wirings 140 connect the multiple pad electrodes 160 and multiple signal lines (e.g., including scan lines, data lines, and drive voltage lines) formed on the display unit 120.

[0045] Multiple pad electrodes 160 are connected to the output wiring of driver 150. Driver 150 outputs power and various signals for the display to the multiple pad electrodes 160.

[0046] The driver integrated circuit 170 can be mounted on the non-display area (NDA) of the flexible substrate 110. The driver integrated circuit 170 can be mounted on the flexible substrate 110 using an anisotropic conductive film via a chip-on-plastic (COP) method. The driver integrated circuit 170 can be a data driver. However, the function of the driver integrated circuit 170 is not limited to that of a data driver.

[0047] When the driver integrated circuit 170 is mounted on the flexible substrate 110, the multiple wirings 140 can be divided into multiple input wirings 141 connecting multiple pad electrodes 160 and the driver integrated circuit 170, and multiple output wirings 142 connecting the driver integrated circuit 170 and the display unit 120.

[0048] When the non-display area (NDA) is set to be parallel to the display area (DA) (refer to...) Figure 3When this occurs, the dead space outside the display unit 120 increases. The curved region (BA) is included within the non-display region (NDA). The curved region (BA) is curved based on a bending axis, and the center of curvature of the curved region (BA) is located at the bending axis (BX). (See reference...) Figure 1 and Figure 2 The bending axis (BX) is parallel to the x-axis.

[0049] The curved area (BA) can be a region within the non-display area (NDA) including the display unit 120 and the driver integrated circuit 170, for example, a region where multiple output wirings 142 are disposed. The driver integrated circuit 170 and multiple pad electrodes 160 are stacked with the display unit 120 at the rear side of the display unit 120 via the curved area (BA). The flexible display device 100 of the embodiment can minimize the unused space located outside the display unit 120 through the curved area (BA).

[0050] The remaining area in the flexible substrate 110, excluding the curved area (BA), can be flat, and the remaining area in the non-display area (NDA), excluding the curved area (BA), can be referred to as the "data driver area (DDA)".

[0051] An insulating layer 130 is formed on the entire flexible substrate 110, and multiple wirings 140 are formed on the insulating layer 130. The insulating layer 130 is disposed between the electrodes forming the thin-film transistors included in the display unit 120 to insulate the electrodes. The insulating layer 130 may include multiple layers, including a barrier layer, a buffer layer, a gate insulating layer, an interlayer insulating layer, etc., and may include materials such as silicon oxide (SiO2) or silicon nitride (SiN). x Inorganic materials, for example. Multiple wirings 140 include metals.

[0052] The insulating layer 130 is less flexible than the multiple wirings 140, and the insulating layer 130 is brittle, making it susceptible to damage from external forces. Therefore, the insulating layer 130 in the bending region (BA) will be damaged by the tensile force caused by bending, resulting in cracks. The initial cracks will then propagate to other areas of the insulating layer 130. Cracks in the insulating layer 130 lead to breaks in the wiring, resulting in display defects in the flexible display device 100.

[0053] The insulating layer 130 includes a cut 180 formed in the bending region (BA). The cut 180 may be formed in the bending region (BA) with a predetermined constant width extending in a direction parallel to the bending axis (BX) (x-axis direction). Since the cut 180 is formed in the insulating layer 130 in the bending region (BA), cracks in the insulating layer 130 due to bending stress can be suppressed, and breakage of the wiring 140 due to cracks in the insulating layer 130 can also be prevented.

[0054] Figures 1 to 4 An embodiment is shown in which a cut 180 is formed in a curved region (BA). When a cut 180 is formed in a curved region (BA), the width w1 of the cut 180 (refer to...) Figure 4 The width w1 of the bend (BA) can be equal to or greater than the width measured at the top surface of the flexible substrate 110. However, the width w1 of the cut 180 is not limited to this.

[0055] The cutout 180 includes two inclined sidewalls (a first sidewall and a second sidewall) 181 and 182 and a bottom surface 183 disposed between the two sidewalls 181 and 182. Multiple output wirings 142 are formed on the insulating layer 130 along the surface shape of the insulating layer 130 in which the cutout 180 is formed. For example, the multiple output wirings 142 are formed between the driver integrated circuit 170 and the display unit 120, extending along the top surface, the first sidewall 181, the bottom surface 183, and the second sidewall 182 of the insulating layer 130.

[0056] exist Figure 3 and Figure 4 In this configuration, the length direction of each of the multiple output wirings 142 is substantially the same as the width direction (y-axis direction) of the cutout 180.

[0057] The first sidewall 181 and the second sidewall 182 of the cut 180 are not formed by vertical sidewalls, but by inclined sidewalls, and the width w2 of each of the first sidewall 181 and the second sidewall 182 (see reference) Figure 4 The depth (d) is equal to or greater than 180 degrees of the incision (refer to...) Figure 4 For example, the width w2 of each of the first sidewall 181 and the second sidewall 182 can be approximately 10 to approximately 50 times the depth (d) of the cut 180.

[0058] Thus, the first sidewall 181 and the second sidewall 182 of the cut 180 are gently sloping sidewalls. Because the ratio of each width w2 of the first sidewall 181 and the second sidewall 182 to the depth (d) of the cut 180 increases, the first sidewall 181 and the second sidewall 182 become very gently sloping sidewalls. Therefore, the multiple output wirings 142 formed along the surface shape of the cut 180 can prevent short circuits from occurring during the patterning process.

[0059] Multiple wirings 140 are formed by depositing a metal layer on the insulating layer 130 in the non-display area (NDA) and then patterning the metal layer via a photolithography process other than dry etching. If the metal layer is left between unwanted areas (i.e., multiple wirings 140), the signal will not be accurately transmitted to the display unit 120 because short circuits will occur between the wirings 140.

[0060] The display unit 120 is sealed by the sealing portion 190 so as not to come into contact with the outside air. For protection, the insulating layer 130 of the non-display area (NDA) and the multiple wirings 140 are covered by the passivation layer 195.

[0061] Figure 5A A partial top view of the non-display area of ​​a flexible display device according to a comparative example is shown. Figure 5B Showing the VV intercept along the line Figure 5A A schematic cross-sectional view of a flexible display device. Figure 5A and Figure 5B In this context, it is assumed that the flexible substrate is flat before the curved region is formed.

[0062] Reference Figure 5A and Figure 5B In the flexible display device of the comparative example, the insulating layer 130a includes a notch 180a formed in the non-display area (NDA), the notch 180a including two vertical sidewalls 184. In this case, after depositing a metal layer 145a on the insulating layer 130a and forming a photoresist mask (not shown), when multiple wirings 140a are formed by partially removing the metal layer 145a via dry etching, a portion of the metal layer 145a is not removed and remains around the vertical sidewalls 184. Figure 5A and Figure 5B In the figure, reference numeral 146 indicates the remaining metal.

[0063] Unlike wet etching, in dry etching, the etching direction is set in one direction ( Figure 5B In the vertical direction, since the portion of metal layer 145a that contacts the vertical sidewall 184 has a greater thickness than the retained portion of metal layer 145a, even though the retained portion of metal layer 145a is completely removed, the portion of metal layer 145a that contacts the vertical sidewall 184 can be retained. Thus, the remaining metal 146 contacts two adjacent wirings 140a, thereby causing a short circuit between wirings 140a.

[0064] Figure 5C This is a schematic cross-sectional view showing the curved area of ​​a flexible display device according to a comparative example.

[0065] Reference Figure 5CThe insulating layer 130a of the non-display area (NDA) and the multiple wirings 140a are covered by a passivation layer 195a including organic material. When the curved area (BA) is formed in the flexible substrate 110a as a comparative example, the passivation layer 195a will detach due to the steep slope of the vertical sidewall 184 of the cutout 180a.

[0066] For example, some passivation layers 195a may separate from the insulating layer 130a and multiple wirings 140a. Figure 5C In the diagram, the portion of the passivation layer 195a that has separated is indicated by arrow C. In this case, moisture and oxygen contained in the outside air permeate the separated portion of the passivation layer 195a, causing the passivation layer 195a to deteriorate.

[0067] Figure 6A A partial top view of the non-display area of ​​the flexible display device according to an embodiment is shown. Figure 6B Showing the section intercepted along line VI-VI Figure 6A A schematic cross-sectional view of a flexible display device. Figure 6A and Figure 6B In this context, it is assumed that the flexible substrate is flat before the curved region is formed.

[0068] Reference Figure 6A and Figure 6B The insulating layer 130 of the flexible display device 100 of the embodiment includes a cut 180 formed in the non-display area (NDA), the cut 180 including an inclined first sidewall 181 and a second sidewall 182 satisfying the condition “w2≥d”. The reference numeral w2 indicates the width of each of the first sidewall 181 and the second sidewall 182, and the reference numeral d indicates the depth of the cut 180.

[0069] Because the first sidewall 181 and the second sidewall 182 are formed with gentle slopes, the thickness of the metal layer 145 deposited on the first sidewall 181 and the second sidewall 182 is substantially the same as the thickness of the metal layer 145 deposited on the top surface of the insulating layer 130 and the bottom surface 183 of the notch 180. Therefore, when multiple wirings 140 are formed by removing a portion of the metal layer 145 by dry etching after forming the photoresist mask, the metal layer 145 disposed on the first sidewall 181 and the second sidewall 182 is completely removed without any residue, thus preventing short circuits between the wirings 140.

[0070] Return to reference Figure 2The insulating layer 130 of the non-display area (NDA) and the multiple wirings 140 are covered by a passivation layer 195 comprising an organic material. In one embodiment, when the bending area (BA) is formed in the flexible substrate 110, the problem of passivation layer 195 detachment can be suppressed. That is, because the passivation layer 195 has excellent adhesion to the first sidewall 181 and the second sidewall 182 due to the gentle slope of the first sidewall 181 and the second sidewall 182, the passivation layer 195 can be prevented from detaching in the bending area (BA).

[0071] When the bending region (BA) is formed by bending the flexible substrate 110, tensile stress is applied to each layer included in the bending region (BA).

[0072] In one embodiment of the flexible display device 100, such as Figure 6B As shown, the first sidewall 181 and the second sidewall 182 of the cutout 180 may have a convex shape (e.g., an upward-facing concave shape) toward the flexible substrate 110. The compressive stress caused by the downward-convex shape is then applied to the layers formed on the first sidewall 181 and the second sidewall 182, namely, the multiple output wirings 142 and the passivation layer 195.

[0073] When the bending region (BA) is formed, the compressive stress applied to the multiple output wirings 142 and the passivation layer 195 partially offsets the tensile stress caused by bending. Therefore, the bending stress (tensile stress) applied to the multiple output wirings 142 and the passivation layer 195 is reduced, and the multiple output wirings 142 and the passivation layer 195 can have high resistance to bending stress.

[0074] Figure 7 A schematic cross-sectional view of a flexible display device according to another embodiment is shown.

[0075] Reference Figure 7 In another embodiment, the insulating layer 130 of the flexible display device 101 includes a plurality of cuts 180 formed in a bending region (BA). The plurality of cuts 180 are spaced apart from each other along the length direction of a plurality of wirings 140. Each of the plurality of cuts 180 is formed extending in a direction parallel to the bending axis (BX) and has a predetermined constant width.

[0076] Despite Figure 7 Two cutouts 180 are shown, but the number of cutouts 180 is not limited to this. Since the construction of the flexible display device 101 according to another embodiment is the same as that of the flexible display device of the embodiment described above, except for the number of cutouts 180, its repeated description will be omitted.

[0077] The detailed structure of display unit 120 and notch 180 will be described below. However, the pixel configuration of display unit 120 and the cross-sectional shape of notch 180 are not limited to the examples below, and they can be modified in various ways.

[0078] Figure 8 Show Figure 1 The equivalent circuit diagram of a pixel is shown in the figure.

[0079] Reference Figure 8 A pixel consists of multiple signal lines (201, 202, 203, 204, 205, 206 and 207), multiple transistors (T1, T2, T3, T4, T5, T6 and T7) connected to the multiple signal lines, a storage capacitor (Cst) and an organic light-emitting diode (OLED).

[0080] The multiple transistors (T1, T2, T3, T4, T5, T6 and T7) include a drive transistor T1, a switch transistor T2, a compensation transistor T3, an initialization transistor T4, an operation control transistor T5, a light-emitting control transistor T6 and a bypass transistor T7.

[0081] Multiple signal lines (201, 202, 203, 204, 205, 206, and 207) include a scan line 201 that transmits a scan signal (Sn), a previous scan line 202 that transmits the previous scan signal Sn-1 to the initialization transistor T4, an illumination control line 203 that transmits an illumination control signal (EM) to the operation control transistor T5 and the illumination control transistor T6, a bypass control line 204 that transmits a bypass signal (BP) to the bypass transistor T7, a data line 205 that crosses the scan line 201 and transmits a data signal (Dm), a drive voltage line 206 that transmits a drive voltage (ELVDD) and is formed substantially parallel to the data line 205, and an initialization voltage line 207 that transmits an initialization voltage (Vint) for initializing the drive transistor T1.

[0082] The gate electrode G1 of the driving transistor T1 is connected to a terminal Cst1 of the storage capacitor Cst. The source electrode S1 of the driving transistor T1 is connected to the driving voltage line 206 via the operation control transistor T5. The drain electrode D1 of the driving transistor T1 is electrically connected to the anode of the organic light-emitting diode (OLED) via the light-emitting control transistor T6. The driving transistor T1 receives a data signal (Dm) according to the switching operation of the switching transistor T2 to supply current (Id) to the organic light-emitting diode (OLED).

[0083] The gate electrode G2 of switching transistor T2 is connected to scan line 201, and the source electrode S2 of switching transistor T2 is connected to data line 205. The drain electrode D2 of switching transistor T2 is connected to the source electrode S1 of driving transistor T1 and is connected to driving voltage line 206 via operation control transistor T5. Switching transistor T2 is turned on according to the scan signal (Sn) transmitted through scan line 201, and then performs a switching operation to transmit the data signal (Dm) transmitted to data line 205 to the source electrode S1 of driving transistor T1.

[0084] The gate electrode G3 of the compensation transistor T3 is connected to the scan line 201. The source electrode S3 of the compensation transistor T3 is connected to the drain electrode D1 of the driving transistor T1 and is connected to the anode of the organic light-emitting diode (OLED) via the light-emitting control transistor T6. The drain electrode D3 of the compensation transistor T3 is connected to the drain electrode D4 of the initialization transistor T4, one terminal Cst1 of the storage capacitor Cst, and the gate electrode G1 of the driving transistor T1. The compensation transistor T3 is turned on according to the scan signal (Sn) transmitted through the scan line 201, and then connects the gate electrode G1 and the drain electrode D1 of the driving transistor T1, thereby connecting the driving transistor T1 as a diode.

[0085] The gate electrode G4 of the initialization transistor T4 is connected to the previous scan line 202, and the source electrode S4 of the initialization transistor T4 is connected to the initialization voltage line 207. The drain electrode D4 of the initialization transistor T4 is connected to one terminal Cst1 of the storage capacitor Cst and the gate electrode G1 of the driving transistor T1 via the drain electrode D3 of the compensation transistor T3. The initialization transistor T4 is turned on according to the previous scan signal Sn-1 transmitted through the previous scan line 202, and then transmits the initialization voltage (Vint) to the gate electrode G1 of the driving transistor T1 to perform an initialization operation for initializing the gate voltage of the gate electrode G1 of the driving transistor T1.

[0086] The gate electrode G5 of the operation control transistor T5 is connected to the light-emitting control line 203, and the source electrode S5 of the operation control transistor T5 is connected to the driving voltage line 206. The drain electrode D5 of the operation control transistor T5 is connected to the source electrode S1 of the driving transistor T1 and the drain electrode S2 of the switching transistor T2.

[0087] The gate electrode G6 of the light-emitting control transistor T6 is connected to the light-emitting control line 203. The source electrode S6 of the light-emitting control transistor T6 is connected to the drain electrode D1 of the driving transistor T1 and the source electrode S3 of the compensation transistor T3. The drain electrode D6 of the light-emitting control transistor T6 is electrically connected to the anode of the organic light-emitting diode (OLED). The operation control transistor T5 and the light-emitting control transistor T6 are simultaneously turned on according to the light-emitting control signal (EM) transmitted through the light-emitting control line 203, and the driving voltage (ELVDD) is compensated by the driving transistor T1 connected by a diode to transmit to the organic light-emitting diode (OLED).

[0088] The gate electrode G7 of bypass transistor T7 is connected to bypass control line 204. The source electrode S7 of bypass transistor T7 is connected to the drain electrode D6 of light-emitting control transistor T6 and the anode of organic light-emitting diode (OLED). The drain electrode D7 of bypass transistor T7 is connected to initialization voltage line 207 and the source electrode S4 of initialization transistor T4. Since bypass control line 204 is connected to the previous scan line 202, the bypass signal (BP) is the same as the previous scan signal Sn-1.

[0089] The other terminal, Cst2, of the storage capacitor Cst is connected to the drive voltage line 206, and the cathode of the organic light-emitting diode (OLED) is connected to the common voltage line 208 of the transmission common voltage (ELVSS). Although Figure 8 The image shows 7 transistors and 1 capacitor, but the pixel structure is not limited to this, and the number of transistors and capacitors may differ in other embodiments.

[0090] Figure 9 Show Figure 1 The image shows an enlarged cross-sectional view of the display unit and non-display area. For better understanding and convenience, Figure 9 This illustrates the case where the flexible substrate is flat. Figure 8 Of the seven transistors shown, the driving transistor T1 and the switching transistor T2 are selectively shown in... Figure 9 middle.

[0091] Figure 9 The cross-sectional structures of the driving transistor T1, switching transistor T2, storage capacitor Cst, and organic light-emitting diode (OLED) shown may differ from the cross-sectional structures of actual flexible display devices. The construction of the driving transistor T1, switching transistor T2, storage capacitor Cst, and organic light-emitting diode (OLED) is described below.

[0092] Reference Figure 9A barrier layer 131 and a buffer layer 132 are formed on the flexible substrate 110. The barrier layer 131 and the buffer layer 132 are used to block impurities from the flexible substrate 110 during the crystallization process for forming polycrystalline silicon (semiconductor) and to reduce the stress applied to the flexible substrate 110. The barrier layer 131 may include multiple layers comprising silicon oxide and silicon nitride layers, and the buffer layer 132 may include a single layer of silicon oxide or silicon nitride.

[0093] A semiconductor, including a drive channel 211 and a switch channel 221, is formed on a buffer layer 132. A drive source electrode 212 and a drive drain electrode 213 are formed on opposite sides of the drive channel 211 to contact the drive channel 211. A switch source electrode 222 and a switch drain electrode 223 are formed on opposite sides of the switch channel 221 to contact the switch channel 221.

[0094] A first gate insulating layer 133 is formed on the semiconductor, and a drive gate electrode 214 and a switch gate electrode 224 are formed on the first gate insulating layer 133. A second gate insulating layer 134 is formed on the drive gate electrode 214 and the switch gate electrode 224, and a second storage electrode 232 is formed on the second gate insulating layer 134. The first gate insulating layer 133 and the second gate insulating layer 134 may include silicon oxide, silicon nitride, etc.

[0095] The storage capacitor Cst includes a first storage electrode 231 and a second storage electrode 232, and a second gate insulating layer 134 is disposed between the first storage electrode 231 and the second storage electrode 232. The first storage electrode 231 may correspond to the driving gate electrode 214. The second gate insulating layer 134 is a dielectric material, and the storage capacitor is determined by the charge charged into the storage capacitor Cst and the voltage between the first storage electrode 231 and the second storage electrode 232.

[0096] The driving transistor T1, the switching transistor T2, and the storage capacitor Cst are covered by an interlayer insulating layer 135. The interlayer insulating layer 135 may include silicon oxide or silicon nitride. A data line 205 is formed on the interlayer insulating layer 135. The data line 205 is connected to the source electrode 222 of the switching transistor T2 through contact holes formed in the interlayer insulating layer 135, the first gate insulating layer 133, and the second gate insulating layer 134.

[0097] Data line 205 is covered by passivation layer 195, on which an organic light-emitting diode (OLED) is formed. Passivation layer 195 may include organic material. The drain electrode 213 of driving transistor T1 is electrically connected to the anode of OLED via light-emitting control transistor (not shown).

[0098] An organic light-emitting diode (OLED) includes a pixel electrode 241, an organic emitting layer 242, and a common electrode 243. The pixel electrode 241 can be an anode serving as a hole injection electrode, and the common electrode 243 can be a cathode serving as an electron injection electrode. The pixel electrode 241 and the common electrode 243 inject holes and electrons into the organic emitting layer 242, respectively. Light is emitted when excitons, which are combinations of injected holes and electrons in the organic emitting layer 242, transition from an excited state to a ground state.

[0099] Reference numeral 196 in the figure indicates a limitation Figure 9 The pixel defining layer 196 is a light-emitting area for each pixel in the display unit 120. The pixel defining layer 196 may include a polyacrylate resin, a polyimide resin, or a silica-based inorganic material. The display unit 120 may be covered by a sealing portion (not shown). The sealing portion may include a first inorganic layer covering the common electrode 243, an organic layer covering the first inorganic layer, and a second inorganic layer covering the organic layer.

[0100] A barrier layer 131, a buffer layer 132, a first gate insulating layer 133, a second gate insulating layer 134, and an interlayer insulating layer 135 form an insulating layer 130, which is formed on the entire flexible substrate 110. A notch 180 is formed in at least one layer including the interlayer insulating layer 135 (which is the topmost layer of the insulating layer 130 formed of multiple layers).

[0101] For example, the notch 180 may be formed in the interlayer insulating layer 135, in the interlayer insulating layer 135 and the second gate insulating layer 134, in the interlayer insulating layer 135, the first gate insulating layer 133 and the second gate insulating layer 134, in the interlayer insulating layer 135, the first gate insulating layer 133, the second gate insulating layer 134 and the buffer layer 132, or in all of the multiple layers from the interlayer insulating layer 135 to the barrier layer 131. Figure 9 An example is shown where a notch 180 is formed in the interlayer insulating layer 135, the first gate insulating layer 133, and the second gate insulating layer 134.

[0102] The cut 180 includes an inclined first sidewall 181 and a second sidewall 182, the width w2 of each of the first sidewall 181 and the second sidewall 182 being equal to or greater than the depth (d) of the cut 180. Figure 9 In this design, the depth (d) of the cut 180 is equal to the total thickness of the interlayer insulating layer 135, the first gate insulating layer 133, and the second gate insulating layer 134. Each of the first sidewall 181 and the second sidewall 182 may have a convex shape (e.g., an upward-facing concave shape) facing the flexible substrate 110.

[0103] Multiple output cabling 142 ( Figure 9An output wiring 142 is shown that contacts data line 205 and may include the same material as data line 205. The output wiring 142 runs along the top surface of interlayer insulation layer 135, the first sidewall 181, and the bottom surface 183 of cutout 180. Figure 9 The top surface of the buffer layer 132, the top surface of the second sidewall 182, and the top surface of the interlayer insulating layer 135 extend from the data line 205 to the driver integrated circuit (not shown). The passivation layer 195 covers multiple output wirings 142 and the insulating layer 130 in the non-display area (NDA).

[0104] Figure 10 A process flow diagram illustrating a method for manufacturing a flexible display device according to an embodiment is shown.

[0105] Reference Figure 10 The manufacturing method of the flexible display device includes: forming an insulating layer in a display area and a non-display area of ​​a flexible substrate (S10); forming a cut in the insulating layer in the non-display area using an etching paste (S20); forming multiple wirings on the insulating layer in which the cut is formed (S30); and forming a curved area by bending the non-display area in which the cut is formed (S40).

[0106] Figure 11A Shown in Figure 10 A schematic cross-sectional view of the flexible display device at S10 is shown in the figure.

[0107] Reference Figure 11A In S10, a flexible substrate 110 is prepared. Next, the flexible substrate 110 is divided into a display area (DA) where display units are disposed and a non-display area (NDA) located outside the display area (DA). An insulating layer 130 is formed on both the display area (DA) and the non-display area (NDA) of the flexible substrate 110. Although not shown, a plurality of transistors and storage capacitors are formed in the display area (DA) simultaneously with the formation of the insulating layer 130.

[0108] Figure 11B Show Figure 10 A schematic cross-sectional view of the flexible display device at S20 is shown in the figure.

[0109] Reference Figure 11B A notch 180 is formed in the insulating layer 130 of the non-display area (NDA) by coating an etching paste 301 onto the insulating layer 130. The etching paste 301 can be applied by methods such as screen printing or inkjet printing, and the etching paste 301 is selectively applied to the portion forming the notch 180. The etching paste 301 can selectively etch inorganic insulating materials such as silicon oxide or silicon nitride.

[0110] Unlike dry etching, etching paste 301 exhibits isotropic etching characteristics. The direction of etching is determined by... Figure 11B The arrows in the diagram indicate that, due to the isotropic etching properties of the etching paste 301, the width w1 of the cut 180 formed on the insulating layer 130 is larger than the width of the initially coated etching paste 301, and the first sidewall 181 and the second sidewall 182 of the cut 180 have gentle slopes, respectively.

[0111] For example, the width w2 of each of the first sidewall 181 and the second sidewall 182 is equal to or greater than the depth (d) of the cut 180. More specifically, the width w2 of each of the first sidewall 181 and the second sidewall 182 can be approximately 10 to approximately 50 times the depth (d) of the cut 180. Furthermore, due to the isotropic etching properties of the etching paste 301, the first sidewall 181 and the second sidewall 182 formed by the etching paste 301 have a convex shape (e.g., an upward-facing concave shape) toward the flexible substrate 110.

[0112] The etching depth can be controlled by the etching paste 301, for example, by adjusting the etching time during S20 to control the depth of the cut 180. Since the etching process using the etching paste 301 is performed at room temperature of approximately 15°C to approximately 25°C, no thermal stress is applied to the flexible substrate 110 and the insulating layer 130 during etching.

[0113] As described above, when using etching paste 301, very gentle sidewalls 181 and 182 (with an inclination of less than an angle of about 45°) can be easily formed, and sidewalls 181 and 182 with a convex shape toward the flexible substrate 110 can be easily formed.

[0114] Figure 11C Show Figure 10 A schematic cross-sectional view of the flexible display device in the third step is shown in the figure.

[0115] Reference Figure 11C In S30, multiple wirings 140 are formed on the insulating layer 130 in the non-display area (NDA). Figure 11C (A wiring diagram is shown). See reference... Figure 6A and Figure 6B As described, when multiple wirings 140 are formed by patterning a metal layer, short circuits between wirings 140 can be prevented because the metal layer is not retained in unintended portions.

[0116] Additionally, the driver integrated circuit 170 is mounted on the non-display area (NDA), and a passivation layer 195 is formed over the entire non-display area (NDA). Since the first sidewall 181 and the second sidewall 182 of the notch 180 have convex shapes facing the flexible substrate 110, compressive stress is applied to the multiple output wirings 142 and the passivation layer 195 formed on the first sidewall 181 and the second sidewall 182.

[0117] Figure 11D Show Figure 10 A schematic cross-sectional view of the flexible display device at S40 is shown in the figure.

[0118] Reference Figure 11D The curved area (BA) is formed by bending the non-display area (NDA) in S40 to form a cut 180. Since the remaining non-display area (NDA) (e.g., the data driver area) is superimposed on the display area (DA) behind the display area (DA), the unused space outside the display unit 120 is reduced.

[0119] When the bending region (BA) is formed, tensile stress is applied to the multiple output wirings 142 and the passivation layer 195 before the bending partially offsets the tensile stress caused by the bending. Compressive stress is also applied to the multiple output wirings 142 and the passivation layer 195. Therefore, the bending stress applied to the multiple output wirings 142 and the passivation layer 195 is reduced.

[0120] Additionally, as referenced Figure 11C As described, due to the gentle slope of the first sidewall 181 and the second sidewall 182 of the cut 180, the adhesion of the passivation layer 195 can be improved, and the defect of passivation layer 195 detachment from the bending region (BA) can be suppressed.

[0121] Although this disclosure has been described in conjunction with specific embodiments, it will be understood that the invention is not limited to the disclosed embodiments, but rather is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A display device, the display device comprising: The substrate, including curved areas; An insulating layer is disposed on the substrate and includes an inclined surface corresponding to the curved region and a flat portion adjacent to the inclined surface but not corresponding to the curved region; Wiring is provided on the inclined surface and the flat portion of the insulation layer in the bending region, and is provided along the inclined surface and the flat portion of the insulation layer in the bending region; as well as An organic layer covers the wiring. The organic layer includes a first portion disposed on the inclined surface of the insulating layer and a second portion disposed on the flat portion of the insulating layer. The thickness of the first portion of the organic layer is greater than the thickness of the second portion of the organic layer, and The inclined surface of the insulating layer includes a curved surface, and The wiring in the curved region is in direct contact with the substrate or the insulating layer corresponding to the bottom surface exposed through the inclined surface.

2. The display device according to claim 1, further comprising: A barrier membrane is disposed on the substrate; A buffer membrane is disposed on the barrier membrane; A semiconductor layer is disposed on the buffer film; A first gate insulating layer is disposed on the semiconductor layer; The gate electrode is disposed on the first gate insulating layer; A second gate insulating layer is disposed on the gate electrode; An interlayer insulating layer is disposed on the second gate insulating layer; as well as The source electrode and drain electrode are disposed on the interlayer insulating layer and connected to the semiconductor layer. The inclined surface is formed on the first gate insulating layer, the second gate insulating layer and the interlayer insulating layer.

3. The display device according to claim 2, wherein, The wiring is connected to the source electrode or the drain electrode.

4. The display device according to claim 3, wherein, A portion of the wiring is disposed on the interlayer insulation layer.

5. The display device according to claim 1, wherein, The insulating layer includes cuts. The cut is formed in the curved region and forms the inclined surface. The cut has sidewalls corresponding to the inclined surface and a bottom surface connected to the sidewalls. The wiring is arranged along the sidewalls of the cut and the bottom surface of the cut.

6. The display device according to claim 1, wherein, Multiple incisions were made, and The plurality of cuts are separated from each other along the length of the wiring.

7. The display device according to claim 1, wherein, The curved region is curved based on the bending axis, and At least one cut is formed extending in a direction parallel to the bending axis.

8. The display device according to claim 1, wherein, The substrate includes a display area and a non-display area. The curved area is included in the non-display area, and The wiring is electrically connected to multiple signal lines included in the display unit disposed in the display area.

9. The display device according to claim 8, further comprising: A driver integrated circuit is formed in the non-display area and electrically connected to the wiring.

10. The display device according to claim 9, wherein, The driver integrated circuit is stacked on the rear side of the display unit through the curved region.

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