Display device

Abstract

Embodiments of the present disclosure provide a display device having improved light extraction efficiency. The display device includes: a base substrate including a pixel area and a non-pixel area; an overcoat layer disposed on the base substrate and formed with a groove portion recessed in a region corresponding to the non-pixel region; a first electrode formed in a region corresponding to the pixel region, and disposed on the overcoat layer; a light emitting layer disposed on the groove portion and the first electrode; and a second electrode disposed on the light emitting layer.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority of Korean Patent Application No. 10 - 2023 - 0196483, filed on December 29, 2023, which is incorporated herein by reference for all purposes as if fully set forth herein. Technical field

[0003] Embodiments of the present disclosure relate to a display device having improved light extraction efficiency. Background art

[0004] As the information age has arrived, the field of displays that visually present electrical information signals has developed rapidly. In response, various display devices with excellent performance such as thinning, lightening, and low power consumption are being developed.

[0005] Specific examples of such display devices include liquid crystal display devices (LCDs), plasma display panel devices (PDPs), field emission display devices (FEDs), organic light - emitting display devices (OLEDs), etc.

[0006] Among them, the organic light - emitting display device does not require a separate light source such as a backlight, and thus has the following advantages: the organic light - emitting display device can be manufactured to be light in weight, thin in shape, and have low power consumption due to low - voltage driving.

[0007] However, in the organic light - emitting display device, a significant portion of the light emitted from the light - emitting layer is lost while passing through various components and being emitted to the outside, such that only about 20% of the light emitted from the light - emitting layer is emitted to the outside.

[0008] The amount of light emitted from the light - emitting layer increases in proportion to the magnitude of the applied current. To increase the brightness of the display device, a larger current should be provided to the display device. Therefore, if the light extraction efficiency is not improved, there may be a problem of increased power consumption. Summary of the invention

[0009] To solve the above problems related to light extraction efficiency, a method of reflecting waveguide - mode light and extracting the light to the outside has been developed by forming a slit in the bank portion of the display device and then disposing a reflective electrode in the slit.

[0010] The position of the slit provided with the reflective electrode can be determined according to the height of the outer coating provided between the bank and the base substrate. That is, the greater the height of the outer coating provided between the bank and the base substrate, the higher the position of the slit can be, and the smaller the height of the outer coating provided between the bank and the base substrate, the lower the position of the slit can be. Therefore, when the height of the outer coating provided between the bank and the base substrate is minimized, the reflective electrode provided in the slit can be located at a position close to the base substrate to effectively block the light in the waveguide mode.

[0011] However, there are the following disadvantages: Due to the nature of the outer coating made of an organic material, it is difficult to form the outer coating provided between the bank and the base substrate to the desired height. In this case, since the reflective electrode located in the slit is set higher than the desired height, there is a phenomenon of light leakage where the light in the waveguide mode does not reach the reflective electrode but reaches the adjacent sub-pixels that emit light of different colors. When such a light leakage phenomenon occurs, there is a problem of color mixing between adjacent sub-pixels, thereby reducing the display quality of the display device.

[0012] In view of this, the inventors of the present disclosure have invented a display device that forms the outer coating provided between the bank and the base substrate to have a minimum height, thereby having improved light extraction efficiency while preventing light leakage.

[0013] Embodiments of the present disclosure can provide a display device that has improved light extraction efficiency by providing a second electrode serving as a reflective electrode in the slit of the bank, so that the light in the waveguide mode that is totally reflected at the interface between the light-emitting layer and the outer coating and then propagates laterally is reflected again by the second electrode and emitted to the outside.

[0014] Embodiments of the present disclosure can provide a display device that can be used with low power consumption as the light extraction efficiency is improved.

[0015] Embodiments of the present disclosure can provide a display device that improves the light leakage phenomenon between the base substrate and the second electrode by defining the groove in which the bank is seated between the color filter and the base substrate to minimize the height of the outer coating provided between the bank and the base substrate.

[0016] Embodiments of the present disclosure can provide a display device that has an improved aperture ratio and display quality because the light leakage phenomenon is improved without increasing the distance between the banks.

[0017] According to an embodiment of the present disclosure, a display device may include: a base substrate including a pixel region and a non-pixel region; an outer coating disposed on the base substrate and having a groove portion recessed in a region corresponding to the non-pixel region; a first electrode formed in a region corresponding to the pixel region and disposed on the outer coating; a light-emitting layer disposed on the groove portion and the first electrode; and a second electrode disposed on the light-emitting layer.

[0018] In another embodiment of the present disclosure, a display device includes: a pixel region and a non-pixel region surrounding the pixel region, defined on a base substrate; an outer coating disposed on the base substrate and having a trench portion; a plurality of first electrodes disposed on the outer coating and spaced apart from each other, each first electrode including an end portion having a lower surface and an upper surface; a bank portion filled in the trench portion, covering the end portion of the first electrode, and having a slit disposed in the non-pixel region; a light-emitting layer disposed on the first electrode and the bank portion; and a second electrode disposed in the slit of the bank portion, wherein the second electrode has a portion located in the slit and closer to the base substrate than the first electrode.

[0019] According to an embodiment of the present disclosure, a display device can be provided in which, by disposing a second electrode serving as a reflective electrode in the slit of the bank portion, light in a waveguide mode that is totally reflected at the interface between the light-emitting layer and the outer coating and then propagates laterally is reflected again by the second electrode and emitted to the outside, thereby improving the light extraction efficiency.

[0020] According to an embodiment of the present disclosure, a display device can be provided that can be used with low power consumption as the light extraction efficiency is improved.

[0021] According to an embodiment of the present disclosure, a display device can be provided in which, by defining a trench in the outer coating where the bank portion is seated between a color filter and the base substrate, the height of the outer coating disposed between the bank portion and the base substrate is minimized, thereby improving the light leakage phenomenon between the base substrate and the second electrode.

[0022] According to an embodiment of the present disclosure, a display device can be provided that has an improved aperture ratio and display quality due to improving the light leakage phenomenon without increasing the distance between the bank portions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a system configuration diagram of a display device according to an embodiment of the present disclosure.

[0024] Figure 2 is Figure 1 a cross-sectional view taken along line A-A' of the display device shown.

[0025] Figure 3 is a view showing fromFigure 2 View of the path of light emitted by the display device.

[0026] Figure 4 View showing the waveguide mode in the display device.

[0027] Figure 5 Cross-sectional view of a display device according to another embodiment of the present disclosure.

[0028] Figure 6 View showing the light leakage phenomenon in the display device.

[0029] Figure 7 View showing the color filter covering part according to an embodiment of the present disclosure.

[0030] Figure 8 View showing the color filter covering part according to an embodiment of the present disclosure.

[0031] Figure 9 View showing the color filter covering part according to an embodiment of the present disclosure.

[0032] Figure 10 View showing the process steps for manufacturing Figure 9 the color filter covering part.

[0033] Figure 11 View showing in Figure 2 region "A" of the optical path of the waveguide mode that appears.

[0034] Figure 12 View showing in Figure 6 region "B" of the optical path of the waveguide mode that appears.

[0035] Figure 13 View showing the process steps for manufacturing a display device according to an embodiment of the present disclosure. Detailed Description

[0036] In the following description of examples or embodiments of the present disclosure, reference will be made to the accompanying drawings, in which specific examples or embodiments that can be implemented are shown by way of example, and in the drawings, the same reference numerals may be used to represent the same or similar components, even if they are shown in different drawings from each other. Further, in the following description of examples or embodiments of the present disclosure, when it is determined that a detailed description of well-known functions and components incorporated herein may make the subject matter in some embodiments of the present disclosure rather unclear, such description will be omitted. Terms such as "comprising", "having", "including", "constituting", "consisting of", and "formed of" as used herein are generally intended to allow the addition of other components, unless these terms are used together with the term "only". As used herein, the singular form is intended to include the plural form, unless the context clearly dictates otherwise.

[0037] Terms such as "first", "second", "A", "B", "(A)", or "(B)" may be used herein to describe elements of the present disclosure. Each of these terms is not used to define the nature, order, sequence, quantity, etc. of the element, but only to distinguish the corresponding element from other elements.

[0038] When referring to a first element being "connected or coupled", "contacting or overlapping" with a second element, etc., it should be interpreted that not only can the first element be "directly connected or coupled" or "directly contacting or overlapping" with the second element, but also a third element can be "interposed" between the first element and the second element, or the first element and the second element can be "connected or coupled", "contacting or overlapping", etc. with each other through a fourth element. Here, the second element may be included in at least one of two or more elements that are "connected or coupled", "contacting or overlapping", etc. with each other.

[0039] When time-related terms such as "after", "subsequent to", "then", "before", etc. are used to describe a process or operation of an element or configuration, or a flow or step in an operation, process, or manufacturing method, these terms may be used to describe a non-consecutive or non-sequential process or operation, unless used together with the terms "directly" or "immediately".

[0040] In addition, when referring to any dimension, relative size, etc., even if the relevant description is not explicitly stated, it should be considered that the numerical value or corresponding information (e.g., level, range, etc.) of the element or feature includes a tolerance or error range that may be caused by various factors (e.g., process factors, internal or external influences, noise, etc.). Further, the term "may" fully encompasses all meanings of the term "can".

[0041] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0042] Figure 1It is a system configuration diagram of a display device according to an embodiment of the present disclosure.

[0043] Reference Figure 1 , the display driving system of the display device 100 according to an embodiment of the present disclosure may include a display panel 1 and a display driving circuit for driving the display panel 1.

[0044] The display panel 1 may include a display area AA for displaying an image and a non-display area NA for not displaying an image. The display panel 1 may include a plurality of sub-pixels SP provided on a substrate substrate 110 to display an image.

[0045] The display panel 1 may include a plurality of signal wirings provided on the substrate substrate 110. For example, the plurality of signal wirings may include data lines DL, gate lines GL, and driving voltage lines DVL.

[0046] Each of the plurality of data lines DL may be provided to extend in a first direction (e.g., a column direction or a row direction), and each of the plurality of gate lines GL may be provided to extend in a direction intersecting the first direction.

[0047] The display driving circuit may include a data driving circuit 11 and a gate driving circuit 12, and may further include a controller 13 for controlling the data driving circuit 11 and the gate driving circuit 12.

[0048] The data driving circuit 11 may output a data signal (also referred to as a data voltage) corresponding to an image signal to the plurality of data lines DL. The gate driving circuit 12 may generate a gate signal GCS and output the gate signal GCS to the plurality of gate lines GL. The controller 13 may convert the input image data Data input from an external host 14 into a data signal DCS format suitable for use in the data driving circuit 11, and supply the converted image data to the data driving circuit 11.

[0049] The data driving circuit 11 may include at least one source driving integrated circuit. For example, each source driving integrated circuit may be connected to the display panel 1 by a tape automated bonding (TAB) method, may be connected to a bonding pad of the display panel 1 by a chip on glass (COG) or chip on panel (COP) method, or may be connected to the display panel 1 by being implemented by a chip on film (COF) method.

[0050] The gate driving circuit 12 may be connected to the display panel 1 by a tape automated bonding (TAB) method, may be connected to a bonding pad of the display panel 1 by a COG or COP method, may be connected to the display panel 1 according to a COF method, or may be formed in the non-display area NA of the display panel 1 in an in-panel gate (GIP) type.

[0051] Reference Figure 1 In the display device 100 according to an embodiment of the present disclosure, each sub-pixel SP may include a light-emitting element ED and a pixel driving circuit SPC for driving the light-emitting element ED. The pixel driving circuit SPC may include a driving transistor DRT, a scanning transistor SCT, and a storage capacitor Cst.

[0052] The driving transistor DRT may drive the light-emitting element ED by controlling the current flowing to the light-emitting element ED. The scanning transistor SCT may transmit a data voltage Vdata to a second node N2 that is a gate node of the driving transistor DRT. The storage capacitor Cst may be configured to hold a voltage for a predetermined period of time.

[0053] The light-emitting element ED may include a first electrode 130, a second electrode 160, and a light-emitting layer 150 disposed between the first electrode 130 and the second electrode 160. The first electrode 130 may be a pixel electrode that participates in the formation of the light-emitting element ED of each sub-pixel SP, and may be electrically connected to a first node N1 of the driving transistor DRT. The second electrode 160 may be a common electrode that participates in the formation of the light-emitting element ED of all sub-pixels SP, and may be applied with a base voltage EVSS.

[0054] For example, the light-emitting element ED may be an organic light-emitting diode (OLED), an inorganic light-emitting diode (LED), or a quantum dot light-emitting element that is a semiconductor crystal that emits light by itself.

[0055] The driving transistor DRT, which is a transistor for driving the light-emitting element ED, may include a first node N1, a second node N2, and a third node N3. The first node N1 may be a source or drain node, and may be electrically connected to the first electrode 130 of the light-emitting element ED. The second node N2 may be a gate node, and may be electrically connected to a source or drain node of the scanning transistor SCT. The third node N3 may be a drain or source node, and may be electrically connected to a driving voltage line DVL that supplies a driving voltage EVDD. Hereinafter, for ease of explanation, it may be described as an example that the first node N1 is a source node and the third node N3 is a drain node.

[0056] The scanning transistor SCT may switch the connection between the data line DL and the second node N2 of the driving transistor DRT. In response to a scan signal SCAN supplied from a scan line SCL that is a kind of gate line GL, the scanning transistor SCT may control the connection between the second node N2 of the driving transistor DRT and the corresponding data line DL among the plurality of data lines DL.

[0057] The storage capacitor Cst may be disposed between the first node N1 and the second node N2 of the driving transistor DRT.

[0058] Figure 1 The structure of the sub-pixel SP shown is merely an example for illustration and may further include at least one transistor or at least one capacitor. Each of the plurality of sub-pixels SP may have the same structure, or a part of the plurality of sub-pixels SP may have different structures. Each of the driving transistor DRT and the scanning transistor SCT may be an n-type transistor or a p-type transistor.

[0059] Figure 2 is Figure 1 a cross-sectional view taken along line A-A' of the display device shown, Figure 3 is a view showing the path of light emitted from the Figure 2 display device.

[0060] Referring to Figure 2 and Figure 3 the display device 100 may include a substrate substrate 110, an outer coating 120, a first electrode 130, a bank 140, a light-emitting layer 150, and a second electrode 160.

[0061] The substrate substrate 110 is for supporting various components of the display device 100 and may be formed of an insulating material such as a glass substrate or a plastic substrate.

[0062] The substrate substrate 110 may include a pixel region PXA in which circuit elements and light-emitting elements ED constituting the sub-pixel SP are formed, and a non-pixel region NPXA surrounding the pixel region PXA around the pixel region PXA. In the present embodiment, the pixel region PXA may be defined as a region where the first electrode 130 is provided, and the non-pixel region NPXA may include a boundary between adjacent sub-pixels SP and / or a non-display region NA.

[0063] Thin film transistors and metal wirings may be located on the substrate substrate 110. For example, the metal wiring may be a driving voltage line DVL. In order to protect the thin film transistors and the metal wirings, a passivation layer 111 may be further provided on the substrate substrate 110.

[0064] The outer coating 120 as a planarization layer for reducing the step degree of the underlying structure may be provided on the substrate substrate 110. For example, the outer coating 120 may be made of an organic material such as polyimide, benzocyclobutene-based resin, or acrylate.

[0065] As the non-pixel region NPXA and a part of the pixel region PXA around the non-pixel region NPXA are recessed, a groove portion 121 may be formed on the upper portion of the outer coating 120. For example, the width of the groove portion 121 formed in the outer coating 120 may be greater than the width of the non-pixel region NPXA, and the groove portion 121 may be formed to bulge outward.

[0066] The first electrode 130 serving as an anode can be independently disposed in each sub-pixel SP. For example, the first electrode 130 can be formed as a transparent electrode such as indium tin oxide (ITO) or indium zinc oxide (IZO), or can be formed as an opaque electrode such as aluminum (Al), copper (Cu), or nickel (Ni). In addition, the first electrode 130 can be formed as a structure in which a transparent electrode and an opaque electrode are laminated.

[0067] The first electrode 130 can be provided in plurality and disposed on the outer coating 120 with spaces therebetween, and each end of the first electrode 130 can overlap with the trench portion 121. In other words, the trench portion 121 is formed to have a width larger than that of the non-pixel region NPXA, and the edge of the trench portion 121 is located below the first electrode 130 such that the end of the first electrode 130 overlaps with the trench portion 121.

[0068] The length of the first electrode 130 overlapping with the trench portion 121 can be at least 0.5 times the wavelength of the light-emitting layer 150 in order to reduce light diffusion caused by diffraction. For example, when the wavelength of the light-emitting layer 150 is 380 nm to 780 nm, the length of the first electrode 130 overlapping with the trench portion 121 can be 190 nm to 390 nm or longer.

[0069] The bank portion 140 is for separating pixels and can be disposed on the outer coating 120. For example, the bank portion 140 can be disposed in and around the trench portion 121 to cover the side portion of the first electrode 130, and a slit 141 can be formed on its upper surface. Specifically, when viewed with the first electrode 130 as a reference, the lower portion of the bank portion 140 can be disposed in the trench portion 121, and the upper portion of the bank portion 140 can be formed to be larger than the width of the trench portion 121 to cover the side portion of the first electrode 130. Thus, the end of the first electrode 130 can be disposed in the bank portion 140.

[0070] The light-emitting layer 150 can be disposed on the first electrode 130 and the bank portion 140. That is, the light-emitting layer 150 can be disposed in the pixel region PXA and the non-pixel region NPXA, and can be disposed in the slit 141 of the bank portion 140 in the non-pixel region NPXA.

[0071] For example, the light-emitting layer 150 can be an organic light-emitting layer including a hole injection layer (HIL), a hole transport layer (HTL), a light-emitting material layer (EML), an electron transport layer (ETL), and an electron injection layer (EIL) as organic compound layers.

[0072] The second electrode 160 serving as a cathode may be disposed on the light-emitting layer 150. For example, the second electrode 160 may be disposed in the pixel region PXA and the non-pixel region NPXA, and may be disposed in the slit 141 of the bank 140 in the non-pixel region NPXA.

[0073] The second electrode 160 in this embodiment may be used as a reflective electrode. To this end, the second electrode 160 may be made of an opaque electrode such as aluminum (Al), copper (Cu), or nickel (Ni) having good reflectivity. In addition, the second electrode 160 may be formed in a structure in which a transparent electrode such as indium tin oxide (ITO) or indium zinc oxide (IZO) and an opaque electrode are laminated.

[0074] In this way, since the second electrode 160 serving as a reflective electrode is disposed in the slit 141 of the bank 140, the light in the waveguide mode can be extracted to the outside to increase the luminance.

[0075] Figure 4 is a view showing the waveguide mode in the display device. The waveguide mode will be described with reference to Figure 4 as follows.

[0076] Reference Figure 4 , among the light generated in the light-emitting layer 150, there is light that is not emitted to the outside and is totally reflected due to the refractive index difference between the light-emitting layer 150 and the outer coating 120 in contact with the light-emitting layer 150. The light totally reflected in this way is not emitted to the outside but is trapped inside. This light is called the light in the waveguide mode. The light in the waveguide mode is totally reflected at the interface between the light-emitting layer 150 and the outer coating 120, and then propagates laterally and disappears, which is the reason for the reduction in the light extraction efficiency.

[0077] To solve the problem of the waveguide mode, in the display device 100 according to an embodiment of the present disclosure, the second electrode 160 may be disposed in the slit 141 of the bank 140. That is, as Figure 3 shown, by disposing the second electrode 160 located in the slit 141 at a position lower than the first electrode 130, even when the light propagates laterally in the waveguide mode, it can be reflected again by the second electrode 160 located in the slit 141 and emitted to the outside.

[0078] Therefore, the light extraction efficiency can be improved, and due to the improvement of the light extraction efficiency, a display device 100 that can be used with low power consumption can be provided.

[0079] According to this embodiment, the slit 141 formed in the bank 140 may be formed between the first electrodes 130, and both sides of the slit 141 may be formed to become narrower in the downward direction. Both sides of the slit 141 may be formed to have a slope of about 30° to 70°. Due to the slope of the slit 141, the light-emitting layer 150 and the second electrode 160 located in the slit 141 may also be formed to have a slope of 30° to 70°. Therefore, the light of the waveguide mode propagating laterally may be totally reflected downward by the inclined surface of the second electrode 160.

[0080] Both sides of the slit 141 may be formed to bulge inward. When both sides of the slit 141 are formed to bulge in this way, the lengths of the light-emitting layer 150 and the second electrode 160 provided in the slit 141 may be increased to improve the light-emitting efficiency. In addition, since light can be provided through various paths compared with the linear light-emitting layer 150, the left and right viewing angles can be improved.

[0081] The display device 100 according to this embodiment may further include a color filter 170.

[0082] The color filters 170 may be provided in plurality and disposed between the base substrate 110 and the outer coating 120, and each color filter 170 may overlap with the pixel region PXA and the non-pixel region NPXA. The plurality of color filters 170 may be formed to correspond to the colors of the respective sub-pixels SP. For example, when the sub-pixel SP is composed of a red sub-pixel, a green sub-pixel, and a blue sub-pixel, the color filters 170 may be composed of a red color filter, a green color filter, and a blue color filter to correspond thereto. When the sub-pixel SP is composed of a white sub-pixel, the color filter 170 may not be provided.

[0083] Due to the presence of the groove portion 121, the color filter 170 may be exposed to the outside of the outer coating 120 in the non-pixel region NPXA. The color filter 170 may be formed to include small molecule dyes, pigments, dispersants, etc., and thus may cause outgassing during the degradation process. Therefore, when the color filter 170 is exposed to the outside of the outer coating 120, the released gas may move toward the sub-pixels, resulting in pixel shrinkage.

[0084] To prevent such pixel shrinkage, the color filter 170 exposed to the groove portion 121 may be covered by the bank 140. In other words, as Figure 2 shown, by forming the slit 141 defined in the bank 140 to have a groove shape with a residual layer in the non-pixel region NPXA, the exposed portion of the color filter 170 can be blocked.

[0085] Figure 5 is a cross-sectional view of a display device according to another embodiment of the present disclosure. In this embodiment, the differences from the embodiment described above will be mainly described.

[0086] Reference Figure 5 , the slit 141 of the display device 200 may be formed in a hole shape without a residual layer of the bank 140 in the non-pixel region NPXA. That is, Figure 2 In the embodiment shown, the slit 141 is formed in a groove shape with a residual layer in the non-pixel region NPXA, but in this embodiment, the slit 141 is formed in a hole shape without a residual layer.

[0087] In this way, since the slit 141 is formed in a hole shape, the bank 140 can be divided by the slit 141 interposed between the respective portions of the bank 140. Therefore, since the second electrode 160 located in the slit 141 can be located closer to the base substrate 110, light leakage can be effectively prevented.

[0088] Figure 6 is a view showing a light leakage phenomenon in a display device. Reference will be made to Figure 6 the following to describe the light leakage phenomenon.

[0089] The second electrode 160 located in the slit 141 of the bank 140 may be located at a higher or lower position according to the distance between the base substrate 110 and the slit 141. As Figure 6 shown, if the distance between the base substrate 110 and the slit 141 is formed to be greater than a preset value, a part of the light that is totally reflected at the interface between the light-emitting layer 150 and the outer coating 120 may not reach the second electrode 160, but may reach an adjacent sub-pixel SP that emits light of a different color. This is called the light leakage phenomenon, and the light leakage phenomenon causes color mixing between adjacent sub-pixels SP, resulting in a decrease in display quality. To solve the light leakage problem, the gap W between the banks 140 can be widened, but in this case, the area of the non-pixel region NPXA may increase, and thus the aperture ratio of the display device 1 may decrease.

[0090] Therefore, in order to solve the light leakage problem without reducing the aperture ratio, in the display device 100 according to this embodiment, the height h between the base substrate 110 and the bank 140 can be minimized.

[0091] Specifically, as Figure 5As shown, the groove portion 121 formed in the outer coating 120 may be recessed between the color filter 170 and the substrate 110 to expose a part of the color filter 170 to the outside. After forming the slit 141 having a hole shape in the bank portion 140 provided in the groove portion 121, by disposing the second electrode 160 in the slit 141, the distance between the substrate 110 and the second electrode 160 can be minimized to prevent light leakage. Therefore, since light leakage can be prevented even without increasing the gap W between the bank portions 140, the aperture ratio and display quality can be improved.

[0092] In the case where the slit 141 of the bank portion 140 is formed in a hole shape without a residual layer in the non-pixel region NPXA, the color filter 170 may be exposed to the outside of the outer coating 120 through the groove portion 121. Thus, when the color filter 170 is exposed to the outside of the outer coating 120, pixel shrinkage may occur. Therefore, a color filter covering portion 180 may be provided to cover the upper portion of the color filter 170.

[0093] The color filter covering portion 180 may be made of an inorganic layer containing an Si-based material to cover the color filter 170. That is, since the Si-based inorganic layer has good light transmittance and is not etched during the dry etching for forming the groove portion 121 of the outer coating 120, the Si-based inorganic layer can protect the color filter 170. Therefore, pixel shrinkage due to the exposure of the color filter 170 can be prevented.

[0094] Figure 7 It is a view showing a color filter covering portion according to an embodiment of the present disclosure. In this embodiment, differences from the above-described embodiment will be mainly described.

[0095] Referring to Figure 7 , the color filter covering portion 280 may cover only the portion of the color filter 170 exposed by the groove portion 121. In other words, the color filter covering portion 280 may be formed to cover only the portion of the color filter 170 that is likely to be affected when etching the outer coating 120 to form the groove portion 121. Therefore, by preventing light loss caused by the color filter covering portion 280 being disposed in the pixel region PXA, the light transmittance can be improved.

[0096] Figure 8 It is a view showing a color filter covering portion according to an embodiment of the present disclosure. In this embodiment, differences from the above-described embodiment will be mainly described.

[0097] Referring to Figure 8, the color filter covering portion 380 may be provided only on the color filter 170 adjacent to the white sub-pixel W-SP. For example, when the sub-pixel SP is composed of a red sub-pixel R-SP, a white sub-pixel W-SP, a green sub-pixel G-SP, and a blue sub-pixel B-SP, the color filter covering portion 380 may be provided only on the color filters 170 of the red sub-pixel R-SP and the blue sub-pixel B-SP adjacent to the white sub-pixel W-SP. This is because mixing red, green, and blue has no significant effect on color perception and color coordinates, but mixing white with red, green, and blue causes color change defects. Therefore, when the color filter covering portion 380 is provided only on the color filter 170 adjacent to the white sub-pixel W-SP, color mixing can be prevented, and at the same time, the light transmittance can be improved.

[0098] Figure 9 is a view showing a color filter covering portion according to an embodiment of the present disclosure. Figure 9 is along Figure 1 cross-sectional view taken along line B-B'.

[0099] Reference Figure 9 , the color filter covering portion 480 may be formed to cover the color filter 170 and the passivation layer 111. In this way, when the color filter covering portion 480 is formed to cover the color filter 170 and the passivation layer 111, the color filter covering portion 480 can be manufactured by reusing the mask for depositing the passivation layer 111. Therefore, since no additional mask is required to manufacture the color filter covering portion 480, the manufacturing cost can be reduced.

[0100] Figure 10 is a view showing the process steps for manufacturing Figure 9 the color filter covering portion. Reference will be made to Figure 10 and the steps for manufacturing the color filter covering portion 480 will be schematically described as follows.

[0101] Reference Figure 10 , first, a passivation layer 111 is formed on the substrate substrate 110 using a passivation mask. After the color filter 170 is formed on the passivation layer 111, the color filter covering portion 480 can be deposited on the color filter 170 and the passivation layer 111 by reusing the passivation mask.

[0102] When the color filter covering portion 480 is manufactured in this way, an outer coating 120 having a groove portion 121 can be formed on the color filter covering portion 480 using an outer coating mask. By performing etching through an etching process such that the bottom surface of the groove portion 121 is located between the outer coating 120 and the color filter 170, the color filter covering portion 480 can be obtained.

[0103] According to this embodiment, the refractive index of the bank portion 140 can be determined to be greater than that of the first electrode 130. For example, when the refractive index of the bank portion 140 is 1.9 to 2.0, the refractive index of the first electrode 130 can be defined as 1.6 to 1.8. In this way, when the refractive index of the bank portion 140 is determined to be greater than that of the first electrode 130, the light generated by the light-emitting layer 150 can be refracted downward and emitted to the outside when passing between the bank portion 140 and the first electrode 130. That is, considering the property that light propagates from a position with a larger refractive index to a position with a smaller refractive index, when the refractive index of the bank portion 140 is determined to be greater than that of the first electrode 130, since the light generated by the light-emitting layer 150 is emitted while being refracted downward at the interface between the first electrode 130 and the bank portion 140, the light extraction efficiency can be improved.

[0104] The refractive index of the bank portion 140 can be determined to be greater than that of the outer coating 120. Therefore, the light generated by the light-emitting layer 150 can be emitted while being refracted in the direction of the bank portion 140 at the interface between the outer coating 120 below the first electrode 130 and the bank portion 140. Therefore, the light loss caused by the lateral propagation of the light in the waveguide mode can be reduced, and the light extraction efficiency can be improved.

[0105] Figure 11 is a view showing the optical path of the waveguide mode that appears in Figure 2 region "A", Figure 12 is a view showing the optical path of the waveguide mode that appears in Figure 6 region "B".

[0106] Referring to Figure 11 and Figure 12 , the display device 100 according to this embodiment is different in that the groove portion 121 formed in the outer coating 120 is formed to bulge outward, and the end portion of the first electrode 130 is formed to protrude outside the outer coating 120 and overlap with the groove portion 121. Due to these differences, in the display device 100 according to this embodiment, since the light of the P path is additionally generated in the waveguide mode, the light extraction efficiency can be improved.

[0107] Specifically, in Figure 12 the display device 1 shown, the light of the waveguide mode propagating laterally at the interface between the light-emitting layer 150 and the outer coating 120 can be reflected by the second electrode 160 and emitted through paths A, B, and C. Therefore, although the light of the waveguide mode can be extracted to the outside, as much light is absorbed as in paths A', B', and C', so the light extraction efficiency may be reduced.

[0108] On the other hand, in the display device 100 according to the present embodiment, by defining an undercut structure below the first electrode 130, the end portion of the first electrode 130 is formed to overlap with the trench portion 121. Therefore, since an additional P path is generated in the waveguide mode, the reduction in light efficiency caused by the above-mentioned paths A', B', and C' can be compensated for.

[0109] Figure 13 is a view showing process steps for manufacturing a display device according to an embodiment of the present disclosure. Reference will be made to Figure 13 The steps for manufacturing a display device will be schematically described as follows.

[0110] First, after patterning the color filter 170 on the base substrate 110, the color filter cover portion 180 may be deposited on the color filter 170 using an Si-based material.

[0111] After forming the outer coating 120 and the first electrode 130, a photolithography process and an etching process may be performed on the outer coating 120 disposed between the first electrodes 130 using a photomask. Accordingly, the trench portion 121 may be formed in the outer coating 120 to overlap with the end portion of the first electrode 130. That is, the trench portion 121 may be formed in a part of the pixel region PXA and the non-pixel region NPXA to overlap with the end portion of the first electrode 130.

[0112] Thereafter, a bank portion 140 having a slit 141 in the non-pixel region NPXA may be formed using a photomask. When the light-emitting layer 150 and the second electrode 160 are sequentially stacked in the pixel region PXA and the non-pixel region NPXA, the display device 100 having the slit 141 with a tapered structure in the non-pixel region NPXA may be manufactured. Although not shown, the display device 100 may further be provided with a packaging layer for flattening the top of the second electrode 160 and preventing moisture from being introduced from the outside.

[0113] A brief description of the above-described embodiments of the present disclosure is as follows.

[0114] According to an embodiment of the present disclosure, a display device may include: a base substrate including a pixel region and a non-pixel region surrounding the pixel region; an outer coating disposed on the base substrate and having a trench portion formed as the non-pixel region and a part of the pixel region surrounding the non-pixel region are recessed; a first electrode provided in plurality and spaced apart on the outer coating and having an end portion overlapping with the trench portion; a bank portion disposed in and around the trench portion to cover a side portion of the first electrode and having a slit formed on an upper surface thereof; a light-emitting layer disposed on the first electrode and the bank portion; and a second electrode disposed on the light-emitting layer.

[0115] According to an embodiment of the present disclosure, the refractive index of the bank portion may be formed to be greater than the refractive index of the first electrode.

[0116] According to an embodiment of the present disclosure, the refractive index of the bank portion may be formed to be greater than the refractive index of the outer coating.

[0117] According to an embodiment of the present disclosure, the second electrode located in the slit may be disposed at a position lower than the first electrode.

[0118] According to an embodiment of the present disclosure, the light propagating to the side portion of the light-emitting layer may be reflected by the second electrode located in the slit and emitted to the outside.

[0119] According to an embodiment of the present disclosure, the slit may be formed between the first electrodes.

[0120] According to an embodiment of the present disclosure, both sides of the slit may be formed such that the width between both sides gradually decreases in the downward direction.

[0121] According to an embodiment of the present disclosure, both sides of the slit may be formed to bulge inward.

[0122] According to an embodiment of the present disclosure, the slit may be formed in the non-pixel region in a groove shape of a residual layer having a bank portion.

[0123] According to an embodiment of the present disclosure, the slit may be formed in the non-pixel region in a hole shape of a residual layer without a bank portion.

[0124] According to an embodiment of the present disclosure, the length of the first electrode overlapping with the trench portion may be at least 0.5 times the wavelength of the light-emitting layer.

[0125] According to an embodiment of the present disclosure, the trench portion may be formed to bulge outward.

[0126] According to an embodiment of the present disclosure, the display device may further include a color filter disposed between the substrate and the outer coating and overlapping with the pixel region and the non-pixel region.

[0127] According to an embodiment of the present disclosure, the trench portion formed in the outer coating may be formed to be recessed between the color filter and the substrate to expose a part of the color filter to the outside.

[0128] According to an embodiment of the present disclosure, the color filter exposed to the outside of the trench portion may be blocked by the bank portion.

[0129] According to an embodiment of the present disclosure, the display device may further include a color filter cover portion covering the upper portion of the color filter.

[0130] According to an embodiment of the present disclosure, the color filter cover portion may include a Si-based material.

[0131] According to an embodiment of the present disclosure, the color filter covering portion may cover only a portion of the color filter that is exposed to the trench portion.

[0132] According to an embodiment of the present disclosure, the color filter covering portion may be provided only on the color filter adjacent to the white sub-pixel.

[0133] According to an embodiment of the present disclosure, the display device may further include a passivation layer provided between the base substrate and the color filter, and the color filter covering portion may cover the color filter and the passivation layer.

[0134] According to an embodiment of the present disclosure, a display device may include: a pixel region and a non-pixel region surrounding the pixel region, defined on a base substrate; an outer coating provided on the base substrate and having trench portions; a plurality of first electrodes provided on the outer coating and spaced apart from each other, each first electrode including an end portion having a lower surface and an upper surface; a bank portion filled in the trench portions, covering the end portions of the first electrodes, and having a slit provided in the non-pixel region; a light-emitting layer provided on the first electrodes and the bank portion; and a second electrode provided in the slit of the bank portion, wherein the second electrode has a portion located in the slit and closer to the base substrate than the first electrode.

[0135] According to an embodiment of the present disclosure, the upper surface is covered more by the bank portion than the lower surface.

[0136] The above description is provided to enable any person skilled in the art to make and use the technical conceptions of the present disclosure, and is provided in the context of a particular application and its requirements. Various modifications, additions, and substitutions to the described embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present disclosure. The above description and the drawings are provided only by way of example to illustrate the technical conceptions of the present disclosure. That is, the disclosed embodiments are intended to illustrate the scope of the technical conceptions of the present disclosure.

Claims

1. A display device, comprising: A base substrate, the base substrate comprising a pixel area and a non-pixel area surrounding the pixel area; an outer coating layer, the outer coating layer being disposed on the base substrate and having a groove portion formed as the non-pixel region and a portion of the pixel region around the non-pixel region are recessed; a plurality of first electrodes disposed on the outer coating layer and spaced apart from each other, each of the first electrodes having an end portion overlapping the groove portion; a bank portion, the bank portion being provided in and around the groove portion and covering a side portion of the first electrode, and having a slit formed on an upper surface of the bank portion; a light-emitting layer, the light-emitting layer being disposed on the first electrode and the bank; as well as A second electrode is disposed on the light-emitting layer.

2. The display device according to claim 1, wherein: The refractive index of the bank is formed to be greater than the refractive index of the first electrode.

3. The display device according to claim 1, wherein: The refractive index of the bank is formed to be greater than the refractive index of the overcoat layer.

4. The display device according to claim 1, wherein: The second electrode has a portion located in the slit provided at a lower vertical position than the first electrode.

5. The display device according to claim 1, wherein: The second electrode located in the slit reflects the light propagating toward the side of the light emitting layer and emits the light to the outside.

6. The display device according to claim 1, wherein: The slits are formed between the plurality of first electrodes.

7. The display device according to claim 1, wherein: Both sides of the slit are formed to have a width therebetween that gradually decreases in a downward direction.

8. The display device according to claim 1, wherein: Both sides of the slit are formed to be convex inwardly.

9. The display device according to claim 1, wherein: The slit is formed in the non-pixel region in a groove shape having a residual layer of the bank.

10. The display device according to claim 1, wherein: The slit is formed in the non-pixel region in a hole shape having no residual layer of the bank.

11. The display device according to claim 1, wherein: A length of the first electrode overlapping the groove portion is at least 0.5 times the wavelength of the light emitting layer.

12. The display device according to claim 1, wherein: The groove portion is formed to protrude outward.

13. The display device according to claim 1, further comprising: A color filter is disposed between the base substrate and the overcoat layer and overlaps the pixel area and the non-pixel area.

14. The display device according to claim 13, wherein: The groove portion formed in the overcoat layer is formed to be recessed between the color filter and the base substrate to expose a portion of the color filter to the outside.

15. The display device according to claim 14, wherein: A portion of the color filter exposed to the outside of the groove portion is shielded by the bank portion.

16. The display device according to claim 13, further comprising: A color filter covering portion covers an upper portion of the color filter.

17. The display device according to claim 16, wherein: The color filter cover includes a Si-based material.

18. The display device according to claim 16, wherein: The color filter covering portion covers only a portion of the color filter exposed to the groove portion.

19. The display device according to claim 16, wherein: The color filter cover is disposed only on the color filter adjacent to the white sub-pixel.

20. The display device according to claim 16, further comprising: a passivation layer disposed between the base substrate and the color filter, The color filter covering part covers the color filter and the passivation layer.

21. A display device, comprising: A pixel region and a non-pixel region surrounding the pixel region are defined on a base substrate; an outer coating layer disposed on the base substrate and having a groove portion; a plurality of first electrodes disposed on the outer coating and spaced apart from each other, each first electrode comprising an end portion having a lower surface and an upper surface; a bank portion filling the groove portion, covering the end portion of the first electrode, and having a slit disposed in the non-pixel region; A light-emitting layer is disposed on the first electrode and the bank; as well as a second electrode disposed in the slit of the bank, The second electrode has a portion located in the slit and closer to the base substrate than the first electrode.

22. The display device according to claim 21, wherein: The upper surface is covered more by the bank than the lower surface.

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