OLED Panel with Trench Overhang Structure

Abstract

The embodiments described herein generally relate to subpixel circuits that may be utilized in displays, such as organic light emitting diode (OLED) displays. The device includes a substrate, a pixel defining layer (PDL) structure disposed over a section of the substrate, an inorganic or metal overhang structure disposed on an upper surface of the PDL structure, and a plurality of subpixels. The PDL structure includes a trench disposed on the top surface of the PDL structure. Each subpixel includes an anode, an OLED material disposed over and in contact with the anode, and a cathode disposed over the OLED material. The inorganic or metal overhang structure has an overhang extension that extends laterally over the trench. An encapsulation layer is disposed over the cathode, the encapsulation layer extending along the top surface of the PDL structure under at least a portion of the inorganic or metal overhang structure.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The embodiments described herein relate generally to displays. More particularly, the embodiments described herein relate to sub-pixel circuits that may be utilized within displays, such as organic light emitting diode (OLED) displays. [Background technology]

[0002] Input devices including display devices may be used within a variety of electronic systems. An organic light-emitting diode (OLED) is a light-emitting diode (LED) in which the light-emitting electroluminescent layer is a film of organic compounds that emits light in response to an electric current. OLED devices are classified as bottom-emitting devices if the emitted light passes through a transparent or semi-transparent bottom electrode and substrate on which the panel is fabricated. Top-emitting devices are classified based on whether the light emitted from the OLED device passes through a lid that is added after the device is fabricated. OLEDs are used today to make display devices for many electronic devices. Today's electronics manufacturers are pushing to reduce the size of these display devices while at the same time providing higher resolution than was possible just a few years ago.

[0003] Currently, the patterning of OLED pixels is based on processes that limit panel size, pixel resolution, and substrate size. Photolithography should be used to pattern the pixels, rather than utilizing fine metal masks. Currently, the patterning of OLED pixels requires the lifting of the organic material after the patterning process. When lifted, the organic material creates particle problems that impair OLED performance. Therefore, there is a need in the art for a sub-pixel circuit that can increase the number of pixels per inch and provide improved OLED performance. Summary of the Invention

[0004] In one embodiment, a device having a plurality of subpixels is provided. Each subpixel includes a section of a substrate and first and second pixel-defining layers (PDLs) including a non-conductive material disposed on the section of the substrate, each of the first and second PDL structures having a trench disposed between a peripheral portion of a top surface of each of the first and second PDL structures. Each subpixel further includes first and second inorganic overhangs, each of the first and second inorganic overhangs being defined by an overhang extension of an inorganic layer disposed on a pair of sidewalls and a peripheral portion of a top surface of the first and second PDL structures. The overhang extensions extend laterally over the trench to define the first and second PDL overhangs. Each subpixel further includes an anode, an organic light-emitting diode (OLED) material disposed on the anode and the inorganic layer, and a cathode disposed on the OLED material. The cathode, the OLED material disposed on the inorganic layer, and the inorganic layer disposed on the peripheral portions of the top surfaces of the first and second PDL structures extend past the peripheral portions of the top surfaces of the first and second PDL layers to define an overhanging extension. An encapsulation layer is disposed over each subpixel and contacts the cathode, sidewalls of the cathode, the OLED material, and the inorganic layer, a lower surface of each of the overhanging extensions of the inorganic layer, and a portion of the top surface of the trench disposed between the peripheral portions of each of the first and second PDL structures.

[0005] In another embodiment, a device is provided having a plurality of subpixels. Each subpixel includes a section of a substrate and a first and a second PDL including a non-conductive material disposed on the section of the substrate, each of the first and second PDL structures having a trench disposed between a peripheral portion of a top surface of each of the first and second PDL structures. Each subpixel further includes a first and a second metal overhang, each of the first and second metal overhangs being defined by an overhang extension of a metal layer disposed on a peripheral portion of a top surface of the first and second PDL structures. The overhang extension extends laterally over the trench to define the first and second metal overhangs. Each subpixel further includes an inorganic layer disposed on sidewalls of the first and second PDL structures and on the metal layer disposed on the peripheral portion of the top surface of the first and second PDL structures. Each subpixel further includes an anode, an OLED material disposed on the anode and on the inorganic layer disposed on the sidewalls, the peripheral portion of the top surface, and the overhanging extensions of the first and second PDL structures, and a cathode disposed on the OLED material. The cathode disposed on the OLED material is disposed on the anode, on the inorganic layer disposed on the sidewalls of the first and second PDL structures, on the metal layer disposed on the peripheral portion of the top surface of the first and second PDL structures, and on the overhanging extensions of the metal layer. The cathode extends to contact the outer sidewalls of the OLED material, the inorganic layer, and the overhanging extensions of the metal layer. An encapsulation layer is disposed on each subpixel, and the encapsulation layer contacts the cathode, the sidewalls of the cathode, the OLED material, the inorganic layer, and the overhanging extensions of the metal layer, a lower surface of each of the overhanging extensions of the metal layer, and a portion of the top surface of the trench disposed between the peripheral portions of each of the first and second PDL structures.

[0006] In another embodiment, a device is provided having a plurality of subpixels. Each subpixel includes a section of a substrate and a first and a second PDL including an inorganic material disposed on the section of the substrate, each of the first and second PDL structures having a trench disposed between a peripheral portion of a top surface of each of the first and second PDL structures. Each subpixel further includes a first and a second metal overhang, each of the first and second metal overhangs being defined by an overhanging extension of a metal layer disposed on a peripheral portion of a top surface of the first and second PDL structures. The overhanging extension extends laterally over the trench to define the first and second metal overhangs. Each subpixel further includes an anode and an OLED material disposed on the anode, on the sidewalls of the first and second PDL structures, on the metal layer disposed on the peripheral portion of the top surface, and on the overhanging extension of the first and second PDL structures. Each subpixel further includes a cathode disposed on the OLED material. A cathode is disposed on the OLED material and is disposed over the anode, over the sidewalls of the first and second PDL structures, over a metal layer disposed on a peripheral portion of the top surface of the first and second PDL structures, and over the overhanging extensions of the metal layer. The cathode extends to contact outer sidewalls of the OLED material and the overhanging extensions of the metal layer. An encapsulation layer is disposed over each subpixel and is disposed between the cathode, the sidewalls of the overhanging extensions of the cathode, the OLED material, and the metal layer, a lower surface of each of the overhanging extensions of the metal layer, and a peripheral portion of each of the first and second PDL structures and in contact with a portion of the top surface of the trench.

[0007] In another embodiment, a device is provided having a plurality of subpixels. Each subpixel includes a section of a substrate and a first and a second PDL including an inorganic material disposed over the section of the substrate, each of the first and second PDL structures having a trench disposed between a peripheral portion of a top surface of each of the first and second PDL structures. Each subpixel further includes first and second metal overhangs, each of the first and second metal overhangs being defined by an overhang extension of a metal layer, the metal layer having the overhang extension and an inner portion disposed at the peripheral portion of the top surface of the first and second PDL structures. The overhang extension has a first tapered sidewall and the inner portion has a second tapered sidewall. The overhang extension extends laterally over the trench to define the first and second metal overhangs. Each subpixel further includes an anode and an organic light emitting diode (OLED) material disposed on the anode, on the sidewalls of the first and second PDL structures, on the second tapered sidewall of the inner portion, and on the top surface of the metal layer. Each subpixel further includes a cathode disposed on the OLED material. The cathode disposed on the OLED material is disposed on the anode, on the sidewalls of the first and second PDL structures, on the metal layer disposed on the peripheral portion of the top surface of the first and second PDL structures, and on the overhanging extension of the metal layer. The cathode contacts the second tapered sidewall of the inner portion of the metal layer. An encapsulation layer is disposed on each subpixel, the encapsulation layer contacting the cathode, the sidewalls of the cathode, the OLED material, and the overhanging extension of the metal layer, the underside of the overhanging extension of each of the metal layers, and the peripheral portion of each of the first and second PDL structures, and a portion of the top surface of the trench.

[0008] So that the above-listed features of the present disclosure may be understood in detail, a more particular description of the present disclosure briefly outlined above may be had by reference to embodiments, some of which are illustrated in the accompanying drawings, which should be noted, however, that the accompanying drawings represent only exemplary embodiments and therefore should not be considered as limiting the scope of the present disclosure, which may embrace other embodiments that are equally effective. [Brief description of the drawings]

[0009] [Figure 1A] FIG. 2 is a schematic top view of a first subpixel circuit according to embodiments described herein. [Figure 1B] FIG. 2 is a schematic cross-sectional view of a first subpixel circuit according to embodiments described herein. [Figure 1C] FIG. 2 is a schematic cross-sectional view of an inorganic overhang in a first subpixel circuit according to embodiments described herein. [Figure 1D] FIG. 2 is a schematic cross-sectional view of a first subpixel circuit according to embodiments described herein. [Figure 2A] FIG. 2 is a schematic cross-sectional view of a second subpixel circuit according to embodiments described herein. [Figure 2B] FIG. 13 is a schematic cross-sectional view of a metal overhang in a second subpixel circuit according to embodiments described herein. [Figure 2C] FIG. 2 is a schematic top cross-sectional view of a second sub-pixel circuit having a dotted architecture according to embodiments described herein. [Figure 2D] FIG. 2 is a schematic top cross-sectional view of a second sub-pixel circuit having a line-type architecture according to embodiments described herein. [Figure 3A] FIG. 2 is a schematic cross-sectional view of a third subpixel circuit according to embodiments described herein. [Figure 3B] FIG. 13 is a schematic cross-sectional view of a metal overhang in a third subpixel circuit according to embodiments described herein. [Figure 4A]FIG. 13 is a schematic cross-sectional view of a fourth subpixel circuit according to embodiments described herein. [Figure 4B] FIG. 13 is a schematic cross-sectional view of a metal overhang in a fourth subpixel circuit according to embodiments described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] For ease of understanding, wherever possible, identical reference numerals have been used to designate identical elements common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without additional description.

[0011] The embodiments described herein generally relate to displays. More particularly, the embodiments described herein relate to subpixel circuits that may be utilized within displays, such as OLED displays. In one embodiment that may be combined with other embodiments described herein, the display is a bottom-emitting (BE) or top-emitting (TE) OLED display. In another embodiment that may be combined with other embodiments described herein, the display is a passive matrix (PM) or active matrix (AM) OLED display.

[0012] The first subpixel circuit has a line-type architecture. The first subpixel circuit includes adjacent non-conductive PDL structures having trenches disposed therein. An inorganic overhang is disposed over the non-conductive PDL structures, and a cathode is in contact with a common cathode of the OLED display. The second subpixel circuit, the third subpixel circuit, and the fourth subpixel circuit have a line-type or dot-type architecture. The second subpixel circuit includes adjacent non-conductive PDL structures having trenches disposed therein. A metal overhang is disposed over the adjacent non-conductive PDL structures, and an inorganic layer is disposed thereon. A cathode is in contact with the OED material, the inorganic layer, and an outer sidewall of the overhang extension of the metal layer of the metal overhang. The third subpixel circuit includes adjacent inorganic PDL structures having trenches disposed therein. The third subpixel circuit further includes a metal overhang disposed over the adjacent inorganic PDL structures, and a cathode in contact with a sidewall of the metal overhang. The fourth subpixel circuit includes an adjacent inorganic PDL structure having a trench disposed therein. The fourth subpixel circuit further includes a metal overhang and a cathode in contact with an inner tapered sidewall of the metal overhang.

[0013] Although the figures show two subpixels, the subpixel circuits of the embodiments described herein include multiple subpixels, such as two or more subpixels. Each subpixel has an OLED material configured to emit white, red, green, blue, or other color light when energized. For example, the OLED material of a first subpixel emits red light when energized, the OLED material of a second subpixel emits green light when energized, and the OLED material of a third subpixel emits blue light when energized.

[0014] Figure 1A is a schematic top view of a first subpixel circuit 100. Figure 1B is a cross-sectional view of the first subpixel circuit. Although Figure 1B shows a first subpixel 118a and a second subpixel 118b, the first subpixel circuit 100 of the embodiments described herein may include more than one subpixel 118, such as a third subpixel 118c and a fourth subpixel.

[0015] The first subpixel circuit 100 has a line-type architecture 101D. The first subpixel circuit 100 includes a plurality of subpixels 118, including at least a first subpixel 118a, a second subpixel 118b, and a third subpixel 118c. Each subpixel 118 has an OLED material 106 configured to emit white, red, green, blue, or other color light when energized. For example, when energized, the OLED material 106 of the first subpixel 118a may emit red light, the OLED material of the second subpixel 118b may emit green light, and the OLED material of the third subpixel 118c may emit blue light. Adjacent non-conductive PDL structures 110 define each subpixel 118. The first subpixel circuit 100 has a density of at least 2,000 pixels per inch (ppi). The subpixels 118 are spaced apart from one another by a pitch 122. In some embodiments, the non-conductive PDL structures 110 have substantially the same width 124. The widths 124 of adjacent non-conductive PDL structures 110 are from about 2 to about 6 μm, and the pitch 122 between each subpixel 118 is less than 13 μm.

[0016] The line architecture 101D of the first subpixel circuit 100 further includes a common cathode 120. In one embodiment, which can be combined with other embodiments described herein, the common cathode 120 is electrically connected to one or more bus bars (not shown), which provide current and / or voltage to the common cathode 120. Each subpixel 118 includes a first end of the cathode 108 (shown in FIG. 1D ) in contact with one common cathode 120 and a second end of the cathode 108 in contact with another common cathode 120. That is, each subpixel 118 is in global contact with the common cathode 120 through the cathode 108 of the respective subpixel. The common cathode 120 is disposed above and below the subpixel 118 in each of the plurality of subpixels 118 to provide a conductive path for current to flow from the common cathode 120 to the respective subpixel 118.

[0017] 1C is a schematic cross-sectional view of an inorganic overhang 112 in a first subpixel circuit 100. The first subpixel circuit 100 includes a substrate 102. The substrate 102 has an anode 104 disposed on a top surface 103 thereof. In one embodiment, which can be combined with other embodiments described herein, the anode 104 is pre-patterned on the substrate 102. For example, the substrate 102 is a pre-patterned indium tin oxide (ITO) glass substrate. The anode 104 may include, but is not limited to, chromium, titanium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials.

[0018] A non-conductive PDL structure 110 is disposed on the substrate 102 and on the peripheral portion 105 of the anode 104. The non-conductive material of the non-conductive PDL structure 110 includes one of an organic material or an inorganic material. The organic material of the non-conductive PDL structure 110 includes, but is not limited to, polyimide. The inorganic material of the non-conductive PDL structure 110 includes, but is not limited to, silicon oxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (Si2N2O), magnesium fluoride (MgF2), or a combination thereof. Adjacent non-conductive PDL structures 110 define corresponding respective subpixels 118 and expose the anode 104 of corresponding respective subpixels 118 of the first subpixel circuit 100. Each non-conductive PDL structure 110 on the first subpixel circuit 100 has a trench 110B disposed between the peripheral portions 110A of the top surface of each non-conductive PDL structure 110. The trenches 110B of each non-conductive PDL structure 110 are formed by an isotropic dry etching process after photoresist patterning of each non-conductive PDL structure 110.

[0019] An inorganic layer 113 is disposed on the adjacent non-conductive PDL structure 110 of each subpixel 118. In one embodiment, the inorganic layer 113 is disposed on a portion of the anode 104 and on the adjacent non-conductive PDL structure 110. The inorganic layer 113 of the subpixel 118 resides in the subpixel circuit and further defines the subpixel 118 in each of the first subpixel circuits 100. The inorganic layer 113 includes an inorganic material. The inorganic material includes, but is not limited to, an inorganic silicon-containing material. For example, the silicon-containing material includes an oxide or nitride of silicon, such as silicon oxide (SiO2), silicon nitride (Si3N4), or silicon oxynitride (Si2N2O), or a combination thereof. An inorganic overhang 112 is defined by an overhang extension portion 115 of the inorganic layer 113 disposed on the sidewall 117 of the non-conductive PDL structure 110 and a peripheral portion 110A of the top surface of the non-conductive PDL structure 110. The overhang extension 115 of each inorganic overhang 112 extends laterally past the peripheral portion 110A of the top surface of the non-conductive PDL structure 110 and overhangs a trench 110B of the non-conductive PDL structure 110. The overhang extension has a width 119 of about 0.5 μm to about 1.5 μm. The first subpixel 118 defines an overhang utilizing a trench 110B disposed within the non-conductive PDL structure 110 and an overhang extension 115 extending over the trench 110B. Because the trench 110B is disposed within the non-conductive PDL structure 110, no additional layers need to be disposed over the inorganic PDL structure 110. By reducing the need for additional layers to define the overhang, process costs and design parameters for defining the overhang are reduced, resulting in increased throughput.

[0020] An OLED material 106 is disposed on the anode 104 and inorganic layer 113 of each subpixel 118. A cathode 108 is disposed on the OLED material 106, with the cathode 108 disposed on the anode 104, on the inorganic layer 113 disposed on the sidewalls 117 and peripheral portion 110A of the non-conductive PDL structure 110, and on the overhanging extensions 115 of the inorganic layer 113. In some embodiments, directional evaporation is used to deposit the OLED material 106 and the cathode 108. The directional evaporation of the OLED material 106 and the subsequent directional evaporation of the cathode 108 are performed at a deposition angle that prevents the OLED material 106 and the cathode 108 from being disposed under the overhanging extensions 115 of the respective inorganic overhangs 112 and inside the trenches 110B.

[0021] Each subpixel 118 includes an encapsulation layer 114. The encapsulation layer 114 may be or may correspond to a local passivation layer. The encapsulation layer 114 of each corresponding subpixel 118 is disposed on the cathode 108. The encapsulation layer 114 contacts the cathode 108, the OLED material 106, and the sidewalls 126 of the inorganic layer 113. The encapsulation layer 114 extends under at least a portion of the lower surface 128 of each of the overhang extensions 115. In some embodiments that can be combined with other embodiments described herein, the encapsulation layer 114 is disposed on a top surface 130 of the non-conductive PDL structure 110. In some embodiments that can be combined with other embodiments described herein, a gap 132 exists between the encapsulation layer 114 disposed on one inorganic overhang 112 and the encapsulation layer 114 disposed on an adjacent inorganic overhang 112. The encapsulation layer 114 includes an inorganic material, such as a silicon-containing material. The silicon-containing material may include a material including Si3N4. In some embodiments that can be combined with other embodiments described herein, each subpixel 118 includes a global encapsulation layer 116. The global encapsulation layer 116 is disposed on the encapsulation layer 114. An inkjet layer may be disposed between the global encapsulation layer 116 and the encapsulation layer 114. The inkjet layer may include an acrylic material. In some embodiments that can be combined with other embodiments described herein, the encapsulation layer 114 and the global encapsulation layer 116 are deposited using an isotropic deposition process. The isotropic deposition process deposits the encapsulation layer 114 such that the encapsulation layer 114 contacts the bottom surface 128 of the overhanging extension 115 and the top surface 130 of the non-conductive PDL structure 110. The isotropic deposition process deposits a global encapsulation layer 116 such that it is disposed over encapsulation layer 114 in at least trench 110B.

[0022] 1D is a schematic cross-sectional view of a first subpixel circuit 100. As shown in FIG. 1D, the first subpixel circuit 100 is in global contact with a common cathode 120. The first subpixel circuit 100 having a line-type architecture 101D includes a common cathode 120 that extends above and below each of a plurality of subpixels 118 along the width of the first subpixel circuit 100. The common cathode 120 is disposed on a non-conductive PDL structure 110. Each of the subpixels 118 in the plurality of subpixels 118 on the first subpixel circuit 100 includes a first end 134a of the cathode 108 in contact with one common cathode 120 and a second end 134b of the cathode 108 in contact with another common cathode 120. In one embodiment, which can be combined with other embodiments described herein, the common cathode 120 is electrically connected to one or more bus bars (not shown), which supply current and / or voltage to the common cathode 120. The common cathode 120 is disposed above and below the subpixels 118 in each of the plurality of subpixels 118 to provide a conductive path for current to flow from the common cathode 120 to the respective subpixels 118.

[0023] 2A is a schematic cross-sectional view of a second subpixel circuit 200 having a metal overhang 212 with a cathode 208 extending into contact with an outer sidewall 226 of an overhang extension 215 of an OLED material 206, an inorganic layer 213, and a metal layer 220. Although FIG. 2A shows a first subpixel 218a and a second subpixel 218b, the second subpixel circuit 200 of the embodiments described herein may include more than one subpixel 218, such as a third and fourth subpixel.

[0024] The second subpixel circuit 200 has a dot-type architecture 201C (shown in FIG. 2C) or a line-type architecture 201D (shown in FIG. 2D). The second subpixel circuit 200 includes a plurality of subpixels 218 including at least a first subpixel 218a, a second subpixel 218b, and a third subpixel 218c (not shown). Each subpixel 218 has an OLED material 206 configured to emit white, red, green, blue, or other color light when energized. For example, the OLED material 206 of the first subpixel 218a may emit red light, the OLED material of the second subpixel 218b may emit green light, and the OLED material of the third subpixel 218c may emit blue light when energized. Adjacent non-conductive PDL structures 210 define each subpixel 218. The second subpixel circuit 200 has a density of at least 2,000 pixels per inch (ppi). The subpixels 218 are spaced apart from one another by a pitch 222. In some embodiments, the non-conductive PDL structures 210 have substantially the same width 224. The width 224 of adjacent non-conductive PDL structures is about 2 to about 6 μm, and the pitch 222 between each of the subpixels 218 is less than 13 μm.

[0025] The second subpixel circuit 200 includes a substrate 202. An anode 204 is disposed on a top surface 203 of the substrate 202. In one embodiment, which can be combined with other embodiments described herein, the anode 204 is pre-patterned on the substrate 202. For example, the substrate 202 is a pre-patterned indium tin oxide (ITO) glass substrate. The anode 204 may include, but is not limited to, chromium, titanium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials.

[0026] A non-conductive PDL structure 210 is disposed on the substrate 202 and on the peripheral portion 205 of the anode 204. The non-conductive PDL structure 210 includes a non-conductive material. The non-conductive material of the non-conductive PDL structure 210 includes one of an organic material or an inorganic material. The organic material of the non-conductive PDL structure 210 includes, but is not limited to, polyimide. The inorganic material of the non-conductive PDL structure 210 includes, but is not limited to, silicon oxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (Si2N2O), magnesium fluoride (MgF2), or combinations thereof. Adjacent non-conductive PDL structures 210 define corresponding respective subpixels 218 and expose the anode 204 of the corresponding respective subpixels 218 of the second subpixel circuit 200. Each non-conductive PDL structure 210 on the second subpixel circuit 200 has a trench 210B disposed between peripheral portions 210A of the top surface of each non-conductive PDL structure 210. The trench 210B of each non-conductive PDL structure 210 is formed by an isotropic dry etching process.

[0027] 2B is a schematic cross-sectional view of a metal overhang in the second subpixel circuit 200. A metal layer 220 is disposed on adjacent non-conductive PDL structures 210 of each subpixel 218. The metal material of the metal layer 220 may include, but is not limited to, molybdenum, chromium, titanium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials. The metal overhangs 212 are defined by overhanging extensions 215 of the metal layer 220 disposed on the peripheral portion 210A of the top surface of the non-conductive PDL structures 210. The overhanging extensions 215 of each metal overhang 212 extend laterally past the peripheral portion 210A of the top surface of the non-conductive PDL structures 210 and overhang the trench 210B area of ​​the non-conductive PDL structures 210. The width 219 of the overhanging extensions 215 is between about 0.5 μm and about 1.5 μm. In one example, the overhang extension 215 of the metal layer 220 is formed by a dry etching process, and the metal layer 220 is further formed by a wet etching process. The second subpixel 218 utilizes a trench 210B disposed in the non-conductive PDL structure 210 and an overhang extension 215 extending over the trench 210B to define an overhang. Because the trench 210B is disposed in the non-conductive PDL structure 210, no additional layers need to be disposed over the inorganic PDL structure 310. By reducing the need for additional layers to define the overhang, the process costs and design parameters for defining the overhang are reduced, resulting in increased throughput.

[0028] An inorganic layer 213 is disposed on adjacent non-conductive PDL structures 210 of each subpixel 218 and on the top surface 211 of the metal layer 220. In one embodiment, the inorganic layer 213 is disposed on portions of the anode 204, adjacent non-conductive PDL structures 210, and on the top surface 211 of the metal layer 220. The inorganic layer 213 of the subpixel 218 resides in the subpixel circuit and further defines each subpixel 218 in the second subpixel circuit 200. The inorganic layer 213 includes an inorganic material. The inorganic material includes, but is not limited to, an inorganic silicon-containing material. For example, the silicon-containing material includes an oxide or nitride of silicon, such as silicon oxide (SiO2), silicon nitride (Si3N4), or silicon oxynitride (Si2N2O), or a combination thereof.

[0029] An OLED material 206 is disposed on the anode 204 and inorganic layer 213 of each subpixel 218. In some embodiments, the OLED material 206 is disposed on the anode 204 and inorganic layer 213 of each subpixel 218 using a directional evaporation process. The directional evaporation process deposits the OLED material 206 on the anode 204 and inorganic layer 213 until a target thickness is reached. During the directional evaporation process, a layer of the OLED material 206 is deposited on the outer sidewalls 226 of the inorganic layer 213 and metal layer 220 of each subpixel 218. The layer of the OLED material 206 is removed using, for example, a laser etching process. A cathode 208 is disposed on the OLED material 206, the cathode 208 being disposed on the anode 204, the inorganic layer 213 disposed on the sidewalls 217 of the non-conductive PDL structure 210, the metal layer 220 disposed on the peripheral portion 210A, and the overhanging extension portion 215 of the metal layer 220. The cathode extends into contact with the outer sidewalls 226 of the overhanging extensions 215 of the OLED material 206, the inorganic layer 213, and the metal layer 220. In some embodiments, the cathode 208 is disposed on the OLED material 206 using a directional deposition process and disposed along the outer sidewalls 226 of the overhanging extensions 215 of the OLED material 206, the inorganic layer 213, and the metal layer 220. A current and / or voltage is provided to the metal layer 220 of each subpixel 218. The contact between the cathode 208 and the metal layer 220 forms a conductive path for current to flow from the metal layer 220 to each subpixel 118.

[0030] Each subpixel 218 includes an encapsulation layer 214. The encapsulation layer 214 may be or may correspond to a local passivation layer. The encapsulation layer 214 of each corresponding subpixel 218 is disposed over the cathode 208. The encapsulation layer 214 contacts the cathode 208, the OLED material 206, and the outer sidewall 226 of the inorganic layer 213. The encapsulation layer 214 extends under at least a portion of the lower surface 228 of each of the overhanging extensions 215. In some embodiments that can be combined with other embodiments described herein, the encapsulation layer 214 is disposed over a top surface 230 of the non-conductive PDL structure 210. In some embodiments that can be combined with other embodiments described herein, a gap 232 exists between the encapsulation layer 214 disposed over one metal overhang 212 and the encapsulation layer 214 disposed over an adjacent metal overhang 212. The encapsulation layer 214 includes an inorganic material, such as a silicon-containing material. The silicon-containing material may include a material including Si3N4. In some embodiments that can be combined with other embodiments described herein, each subpixel 218 includes a global encapsulation layer 216. The global encapsulation layer 216 is disposed on the encapsulation layer 214. An inkjet layer may be disposed between the global encapsulation layer 216 and the encapsulation layer 214. The inkjet layer may include an acrylic material. In some embodiments that can be combined with other embodiments described herein, the encapsulation layer 214 and the global encapsulation layer 216 are deposited using an isotropic deposition process. The isotropic deposition process deposits the encapsulation layer 214 such that the encapsulation layer 214 contacts the bottom surface 228 of the overhanging extension 215 and the top surface 230 of the non-conductive PDL structure 210. The isotropic deposition process deposits a global encapsulation layer 216 such that it is disposed over encapsulation layer 214 in at least trench 210B.

[0031] FIG 2C is a schematic top cross-sectional view of a second subpixel circuit 200 having a dotted architecture 201C. The dotted architecture 201C may correspond to the second subpixel circuit 200, the third subpixel circuit 300, or the fourth subpixel circuit 400. FIG 2D is a schematic top cross-sectional view of a second subpixel circuit 200 having a lined architecture 201D. The lined architecture 201D may correspond to the first subpixel circuit 100, the second subpixel circuit 200, the third subpixel circuit 300, or the fourth subpixel circuit 400. Each of the top cross-sectional views of FIG 1C and 1D is taken along section line 2' of FIG 2A.

[0032] The dot-type architecture 201C includes a plurality of pixel apertures 223A, each of which is surrounded by a non-conductive PDL structure 210 that defines each of the sub-pixels 218 of the dot-type architecture 201C. The line-type architecture 201D includes a plurality of pixel apertures 223B, each of which is bordered by a non-conductive PDL structure 210 that defines each of the sub-pixels 218 of the line-type architecture 201D.

[0033] Figure 3A is a schematic cross-sectional view of a third subpixel circuit 300. Although Figure 3A shows a first subpixel 318a and a second subpixel 318b, the third subpixel circuit 300 of embodiments described herein may include more than one subpixel 318, such as a third and a fourth subpixel.

[0034] The third subpixel circuit 300 has a dot-type architecture 201C (shown in FIG. 2C) or a line-type architecture 201D (shown in FIG. 2D). The third subpixel circuit 300 includes a plurality of subpixels 318 including at least a first subpixel 318a, a second subpixel 318b, and a third subpixel 318c (not shown). Each subpixel 318 has an OLED material 306 configured to emit white, red, green, blue, or other color light when energized. For example, the OLED material 306 of the first subpixel 318a may emit red light, the OLED material of the second subpixel 318b may emit green light, and the OLED material of the third subpixel 318c may emit blue light when energized. Adjacent inorganic PDL structures 310 define each subpixel 318. The third subpixel circuit 300 has a density of at least 2,000 pixels per inch (ppi). The subpixels 318 are spaced apart from one another by a pitch 322. In some embodiments, the inorganic PDL structures 310 have substantially the same width 324. The widths 324 of adjacent inorganic PDL structures 310 are from about 2 to about 6 μm, and the pitch 322 between each of the subpixels 318 is less than 13 μm.

[0035] The third subpixel circuit 300 includes a substrate 302. An anode 304 is disposed on a top surface 303 of the substrate 302. In one embodiment, which can be combined with other embodiments described herein, the anode 304 is pre-patterned on the substrate 302. For example, the substrate 302 is a pre-patterned indium tin oxide (ITO) glass substrate. The anode 304 may include, but is not limited to, chromium, titanium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials.

[0036] An inorganic PDL structure 310 is disposed on the substrate 302 and on the peripheral portion 305 of the anode 304. The inorganic PDL structure 310 includes an inorganic material. The inorganic material of the inorganic PDL structure 310 includes, but is not limited to, silicon oxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (Si2N2O), magnesium fluoride (MgF2), or a combination thereof. Adjacent inorganic PDL structures 310 define corresponding respective subpixels 318 and expose the anode 304 of corresponding respective subpixels 318 of the third subpixel circuit 300. Each inorganic PDL structure 310 on the subpixel circuit 310 has a trench 310B disposed between the peripheral portions 310A of the top surface of each inorganic PDL structure 310. The trench 310B of each inorganic PDL structure 310 is formed by an isotropic dry etching process.

[0037] 3B is a schematic cross-sectional view of a metal overhang in a third subpixel circuit 300. A metal layer 320 is disposed on adjacent inorganic PDL structures 310 of each subpixel 318. The metal material of the metal layer 320 may include, but is not limited to, molybdenum, chromium, titanium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials. The metal overhangs 312 are defined by overhanging extensions 315 of the metal layer 320 disposed on the peripheral portion 310A of the top surface of the inorganic PDL structure 310. The overhanging extensions 315 of each metal overhang 312 extend laterally past the peripheral portion 310A of the top surface of the inorganic PDL structure 310 and overhang the trench 310B area of ​​the inorganic PDL structure 310. The width 319 of the overhanging extensions 315 is between about 0.5 μm and about 1.5 μm. In one example, the overhang extension 315 of the metal layer 320 is formed by a dry etching process, and the metal layer 320 is further formed by a wet etching process. The third subpixel 318 utilizes a trench 310B disposed in the inorganic PDL structure 310 and an overhang extension 315 that extends over the trench 210B to define an overhang. Because the trench 310B is disposed in the inorganic PDL structure 310, no additional layers need to be disposed over the inorganic PDL structure 310. By reducing the need for additional layers to define the overhang, the process costs and design parameters for defining the overhang are reduced, resulting in increased throughput.

[0038] An OLED material 306 is disposed on the anode 304 and inorganic PDL structure 310 of each subpixel 318. In some embodiments, the OLED material 306 is disposed on the anode 304 and inorganic PDL structure 310 of each subpixel 318 using a directional evaporation process. The directional evaporation process deposits the OLED material 306 on the anode 304 and inorganic PDL structure 310 until a target thickness is reached. During the directional evaporation process, a layer of the OLED material 306 is deposited on the outer sidewall 326 of the metal layer 320. The layer of the OLED material 306 is removed using, for example, a laser etching process. A cathode 308 is disposed on the OLED material 306, the cathode 308 being disposed on the anode 304, on the sidewall 317 of the inorganic PDL structure 310, on the metal layer 320 disposed in the peripheral portion 310A, and on the overhanging extension portion 315 of the metal layer 320. The cathode extends to contact the outer sidewall 226 of the overhanging extension 215 of the OLED material 206, the inorganic layer 213, and the metal layer 220. The cathode 308 of each subpixel 318 extends to contact the outer sidewall 326 of the overhanging extension 315 of the OLED material 306 and the metal layer 320. In some embodiments, the cathode 308 is disposed on the OLED material 306 using a directional deposition process and disposed along the outer sidewall 326 of the overhanging extension 315 of the OLED material 306 and the metal layer 320. A current and / or voltage is provided to the metal layer 320 of each subpixel 318. The contact between the cathode 308 and the metal layer 320 forms a conductive path for current to flow from the metal layer 320 to each subpixel 318.

[0039] Each subpixel 318 includes an encapsulation layer 314. The encapsulation layer 314 may be or may correspond to a local passivation layer. The encapsulation layer 314 of each corresponding subpixel 318 is disposed over the cathode 308. The encapsulation layer 314 contacts the cathode 308, the OLED material 306, and the outer sidewalls 326 of the metal layer 320. The encapsulation layer 314 extends under at least a portion of the lower surface 328 of each of the overhang extensions 315. In some embodiments that can be combined with other embodiments described herein, the encapsulation layer 314 is disposed over a top surface 330 of the inorganic PDL structure 310. In some embodiments that can be combined with other embodiments described herein, a gap 332 exists between the encapsulation layer 314 disposed over one metal overhang 312 and the encapsulation layer 314 disposed over an adjacent metal overhang 312. The encapsulation layer 314 includes an inorganic material, such as a silicon-containing material. The silicon-containing material may include a material including Si3N4. In some embodiments that can be combined with other embodiments described herein, each subpixel 318 includes a global encapsulation layer 316. The global encapsulation layer 316 is disposed on the encapsulation layer 314. An inkjet layer may be disposed between the global encapsulation layer 316 and the encapsulation layer 314. The inkjet layer may include an acrylic material. In some embodiments that can be combined with other embodiments described herein, the encapsulation layer 314 and the global encapsulation layer 316 are deposited using an isotropic deposition process. The isotropic deposition process deposits the encapsulation layer 314 such that the encapsulation layer 314 contacts the bottom surface 328 of the overhanging extension 315 and the top surface 330 of the inorganic PDL structure 310. The isotropic deposition process deposits a global encapsulation layer 316 such that it is disposed over encapsulation layer 314 in at least trench 310B.

[0040] Figure 4A is a schematic cross-sectional view of a fourth subpixel circuit 400. Although Figure 4A shows a first subpixel 418a and a second subpixel 418b, the fourth subpixel circuit 400 of embodiments described herein may include more than one subpixel 418, such as a third and a fourth subpixel.

[0041] The fourth subpixel circuit 400 has a dot-type architecture 201C (shown in FIG. 2C) or a line-type architecture 201D (shown in FIG. 2D). The fourth subpixel circuit 400 includes a plurality of subpixels 418 including at least a first subpixel 418a, a second subpixel 418b, and a third subpixel 418c (not shown). Each subpixel 418 has an OLED material 406 configured to emit white, red, green, blue, or other color light when energized. For example, the OLED material 406 of the first subpixel 418a may emit red light, the OLED material of the second subpixel 418b may emit green light, and the OLED material of the third subpixel 418c may emit blue light when energized. Adjacent inorganic PDL structures 410 define each subpixel 418. The fourth subpixel circuit 400 has a density of at least 2,000 pixels per inch (ppi). The subpixels 418 are spaced apart from one another by a pitch 422. In some embodiments, the inorganic PDL structures 410 have substantially the same width 424. The widths 424 of adjacent inorganic PDL structures 410 are between about 2 and about 6 μm, and the pitch 422 between each of the subpixels 418 is less than 13 μm.

[0042] The fourth subpixel circuit 400 includes a substrate 402. An anode 404 is disposed on a top surface 403 of the substrate 402. In one embodiment, which can be combined with other embodiments described herein, the anode 404 is pre-patterned on the substrate 402. For example, the substrate 402 is a pre-patterned indium tin oxide (ITO) glass substrate. The anode 404 may include, but is not limited to, chromium, titanium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials.

[0043] An inorganic PDL structure 410 is disposed on the substrate 402 and on the peripheral portion 405 of the anode 404. The inorganic PDL structure 410 includes an inorganic material. The inorganic material of the inorganic PDL structure 410 includes, but is not limited to, silicon oxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (Si2N2O), magnesium fluoride (MgF2), or a combination thereof. Adjacent inorganic PDL structures 410 define corresponding respective subpixels 418 and expose the anode 404 of corresponding respective subpixels 418 of the fourth subpixel circuit 400. Each inorganic PDL structure 410 on the subpixel circuit 410 has a trench 410B disposed between the peripheral portions 410A of the top surface of each inorganic PDL structure 410. The trench 410B of each inorganic PDL structure 410 is formed by an isotropic dry etching process.

[0044] 4B is a schematic cross-sectional view of a metal overhang 412 in the fourth subpixel circuit 400. A metal layer 420 is disposed on adjacent inorganic PDL structures 410 of each subpixel 418. The metal material of the metal layer 420 includes, but is not limited to, molybdenum, chromium, titanium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials. The metal overhang 412 is defined by an overhanging extension 415 of the metal layer 420 disposed on a peripheral portion 410A of the top surface of the inorganic PDL structure 410. The metal extension 415 has a first tapered sidewall 431 and an inner portion 434 of the metal layer 420 has a second tapered sidewall 433. The overhang extension 415 of each metal overhang 412 extends laterally past the peripheral portion 410A of the top surface of the inorganic PDL structure 410 and overhangs the trench 410B area of ​​the inorganic PDL structure 410. The width 419 of the overhang extension 415 is about 0.5 μm to about 1.5 μm. In one example, the overhang extension 415 of the metal layer 420 is formed by a dry etching process, and the metal layer 420 is further formed by a wet etching process. The fourth subpixel 418 utilizes the trench 410B disposed in the inorganic PDL structure 410 and the overhang extension 415 extending over the trench 410B to define an overhang. Because the trench 410B is disposed in the inorganic PDL structure 410, no additional layers need to be disposed on the inorganic PDL structure 410. By reducing the need for additional layers to define the overhang, process costs and design parameters for defining the overhang are reduced, resulting in increased throughput.

[0045] An OLED material 406 is disposed on the anode 404 and inorganic PDL structure 410 of each subpixel 418. In some embodiments, the OLED material 406 is disposed on the anode 404 and inorganic PDL structure 410 of each subpixel 418 using a directional evaporation process. The directional evaporation process deposits the OLED material 406 on the anode 404 and inorganic PDL structure 410 until a target thickness is reached. During the directional evaporation process, a layer of the OLED material 406 is deposited on the outer sidewall 426 of the metal layer 420. The layer of the OLED material 406 is removed using, for example, a laser etching process. The OLED material 406 deposited on the top surface of the metal layer 420 is separated from the OLED material 406 deposited on the anode 404 and the OLED material 406 deposited along the sidewall 417 of the inorganic PDL structure 410. A cathode 408 is disposed on the LED material 406, the cathode 408 being disposed on the anode 404, on the sidewalls 417 of the inorganic PDL structure 410, on the metal layer 420 disposed in the peripheral portion 410A, and on the overhanging extension 415 of the metal layer 420. The cathode 408 is in contact with a second tapered sidewall 433 at an inner portion 434 of the metal layer 420. In some embodiments, the cathode 408 is disposed on the OLED material 406 using a directional deposition process and is disposed along the outer sidewall 426 of the OLED material 406 and the overhanging extension 415 of the metal layer 420. A current and / or voltage is provided to the metal layer 420 of each subpixel 418. The contact between the cathode 408 and the metal layer 420 forms a conductive path for current to flow from the metal layer 420 to each subpixel 418.

[0046] Each subpixel 418 includes an encapsulation layer 414. The encapsulation layer 414 may be or may correspond to a local passivation layer. The encapsulation layer 414 of each corresponding subpixel 418 is disposed over the cathode 408. The encapsulation layer 414 contacts the cathode 408, the OLED material 406, and the outer sidewalls 426 of the metal layer 420. The encapsulation layer 414 extends under at least a portion of the lower surface 428 of each of the overhang extensions 415. In some embodiments that can be combined with other embodiments described herein, the encapsulation layer 414 is disposed over a top surface 430 of the inorganic PDL structure 410. In some embodiments that can be combined with other embodiments described herein, a gap 432 exists between the encapsulation layer 414 disposed over one metal overhang 412 and the encapsulation layer 414 disposed over an adjacent metal overhang 412. The encapsulation layer 414 includes an inorganic material, such as a silicon-containing material. The silicon-containing material may include a material including Si3N4. In some embodiments that can be combined with other embodiments described herein, each subpixel 418 includes a global encapsulation layer 416. The global encapsulation layer 416 is disposed on the encapsulation layer 414. An inkjet layer may be disposed between the global encapsulation layer 416 and the encapsulation layer 414. The inkjet layer may include an acrylic material. In some embodiments that can be combined with other embodiments described herein, the encapsulation layer 414 and the global encapsulation layer 416 are deposited using an isotropic deposition process. The isotropic deposition process deposits the encapsulation layer 414 such that the encapsulation layer 414 contacts the bottom surface 428 of the overhanging extension 415 and the top surface 430 of the inorganic PDL structure 410. The isotropic deposition process deposits a global encapsulation layer 416 such that it is disposed over encapsulation layer 414 in at least trench 410B.

[0047] In summary, the embodiments described herein relate to forming subpixel circuits that may be utilized in displays, such as organic light-emitting diode (OLED) displays. Adjacent inorganic PDL overhang structures (from a first subpixel circuit) or metal-containing overhang structures (from a second, third, or fourth subpixel circuit) that define each subpixel in the subpixel circuit of the display define the formation of the subpixel circuit using deposition. Each subpixel defines an overhang utilizing a trench disposed in the PDL and an inorganic or metal overhang extension that extends over the trench. Because the trench is disposed in the PDL, no additional layer needs to be disposed on the PDL. By reducing the need for additional layers to define the overhang, the process cost and design parameters for defining the overhang are reduced, resulting in increased throughput.

[0048] While the foregoing is directed to embodiments of the present disclosure, other and additional embodiments of the disclosure may be devised without departing from the basic scope thereof, the scope of which is determined by the following claims.

Claims

1. A device having a plurality of subpixels, each subpixel comprising: A section of the board, first and second pixel definition layer (PDL) structures having trenches disposed therein; first and second overhangs, each of the first and second overhangs being defined by overhanging extensions of layers disposed on at least sidewalls and top surfaces of the first and second PDL structures, the overhanging extensions extending laterally past the trench to define the first and second overhangs; an anode; an organic light emitting diode (OLED) material disposed over the anode and the overhanging extension; a cathode disposed over the OLED material, the cathode comprising: Above the anode, above said layer, and Above said overhanging extension the cathode, A device comprising:

2. further comprising an encapsulation layer, said encapsulation layer comprising: above the cathode; and on a portion of the top surface of the trench disposed between peripheral portions of each of the first and second PDL structures. The device of claim 1 .

3. The device of claim 2 further comprising a global passivation layer disposed over the encapsulation layer and over the first and second PDL structures.

4. The device of claim 1 , wherein the device comprises a line-type architecture.

5. The device of claim 4 , wherein the cathode of each subpixel in the line architecture is in contact with a common cathode.

6. The device of claim 1 , wherein the first and second PDL structures comprise a non-conductive material that is an organic material.

7. The device of claim 1 , wherein the first and second PDL structures comprise a non-conductive material that is an inorganic material.

8. The inorganic material is silicon oxide (SiO 2 ), silicon nitride (Si 3 N 4 ), silicon oxynitride (Si 2 N 2 O), magnesium fluoride (MgF 2 8. The device of claim 7, comprising:

9. A device having a plurality of subpixels, each subpixel comprising: A section of the board, first and second pixel definition layer (PDL) structures having trenches disposed therein; first and second overhangs, each of the first and second overhangs being defined by an overhang extension of an inorganic layer disposed on top of at least the first and second PDL structures, the overhang extensions extending laterally past the trench to define the first and second overhangs; an anode; an organic light emitting diode (OLED) material disposed on the anode and the overhanging extensions of the first and second PDL structures; a cathode disposed over the OLED material, the cathode comprising: Above the anode, on the inorganic layer, and Above said overhanging extension the cathode, A device comprising:

10. further comprising an encapsulation layer, said encapsulation layer comprising: above the cathode; and on a portion of the top surface of the trench disposed between peripheral portions of each of the first and second PDL structures. The device of claim 9 .

11. The device of claim 9 , wherein the device comprises a line architecture or a dot architecture.

12. 10. The device of claim 9, wherein the inorganic layer comprises titanium (Ti), molybdenum (Mo), aluminum (Al), copper (Cu), a transparent conductive oxide (TCO), or a combination thereof.

13. 13. The device of claim 12, wherein the TCO comprises indium zinc oxide (IZO), indium tin oxide (ITO), indium gallium zinc oxide (IGZO), or a combination thereof.

14. A device having a plurality of subpixels, each subpixel comprising: A section of the board, first and second pixel definition layer (PDL) structures comprising an inorganic material, each of the first and second PDL structures having a trench disposed between peripheral portions of a top surface of each of the first and second PDL structures; first and second overhangs, each defined by an overhanging extension of a layer disposed on the peripheral portions of the top surfaces of the first and second PDL structures, the overhanging extensions extending laterally past the trench to define the first and second overhangs; an anode; an organic light emitting diode (OLED) material disposed over the anode, over sidewalls of the first and second PDL structures, over the layer disposed over the peripheral portion of the top surface, and over the overhanging extension; a cathode disposed over the OLED material, the cathode comprising: Above the anode, on the sidewalls of the first and second PDL structures; on the layer disposed on the peripheral portions of the top surfaces of the first and second PDL structures; and On the overhanging extension of the layer the cathode, A device comprising:

15. further comprising an encapsulation layer, said encapsulation layer comprising: Above the cathode, on sidewalls of the overhanging extensions of the cathode, the OLED material, and the layers; on the underside of the overhanging extension of each of said layers; and a top surface of the trench disposed between the peripheral portions of each of the first and second PDL structures; The device of claim 14 .

16. The device of claim 14 , wherein the device comprises a line architecture or a dot architecture.

17. The device of claim 14 , wherein the device includes a local cathode contact.

18. The inorganic material is silicon nitride (Si 3 N 4 ), silicon oxynitride (SiON), magnesium fluoride (MgF 2 ), silicon oxide (SiO 2 15. The device of claim 14, comprising:

19. The device of claim 14 , wherein the layer comprises Ti, Mo, Al, Cu, a TCO, or a combination thereof.

20. 20. The device of claim 19, wherein the TCO comprises IZO, ITO, IGZO, or a combination thereof.

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