Method of manufacturing OLED panel with inorganic pixel encapsulating barrier

Abstract

To provide sub-pixel circuits and methods of forming sub-pixel circuits that may be utilized in a display such as an organic light-emitting diode display.SOLUTION: A device includes a plurality of sub-pixels. Each sub-pixel of the plurality of sub-pixels is defined by adjacent pixel-defining layer structures 126 in a state where inorganic overhang structures 110 are disposed on each of the pixel-defining layer structures. Each sub-pixel includes an anode 104, and a cathode 114 disposed on an organic light-emitting diode material 112 disposed on the anode. The device is fabricated by a process including the steps of: depositing the organic light-emitting diode material and the cathode by vapor deposition; and depositing an encapsulation layer 116 disposed on the cathode.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001]

[0001] Embodiments described herein generally relate to displays. In particular, embodiments described herein relate to subpixel circuits and methods of forming subpixel circuits that may be used in displays such as organic light emitting diode (OLED) displays.

Background Art

[0002]

[0002] Input devices including display devices may be used in various electronic systems. An organic light emitting diode (OLED) is a light emitting diode (LED) that is a film of an organic compound in which an emissive electroluminescent layer emits light in response to an electric current. An OLED device is classified as a bottom emission device when the emitted light passes through a transparent or semi-transparent bottom electrode and a substrate on which the panel is fabricated. An OLED device is classified as a top emission device when the light emitted from the OLED device exits through a lid added after the device is fabricated. OLEDs are currently used to produce display devices installed in many electronic devices. Currently, electronic device manufacturers are providing higher resolutions than just a few years ago while miniaturizing these display devices.

[0003]

[0003] Pixel patterning of OLEDs is currently based on processes that limit panel size, pixel resolution, and substrate size. Instead of using a fine metal mask, it is necessary to use photolithography to pattern the pixels. Currently, pixel patterning of OLEDs requires liftoff of the organic material after the patterning process. When lifted off, the organic material leaves a particle problem that inhibits OLED performance. Accordingly, there is a need in the art for subpixel circuits and methods of forming subpixel circuits that increase the number of pixels per inch and provide improved OLED performance.

Summary of the Invention

[0004]

[0004] In one embodiment, a device is provided. The device includes a plurality of sub-pixels. Each sub-pixel of the plurality of sub-pixels is defined by an adjacent pixel definition layer (PDL) structure with an inorganic overhang structure disposed on the PDL structure. Each sub-pixel has an anode, an organic light-emitting diode (OLED) material disposed on the anode, and a cathode disposed on the OLED material. The device is fabricated by a process including the following plurality of steps. That is, a step of depositing an OLED material on a substrate using evaporation deposition, wherein the OLED material is disposed on and in contact with the anode; a step of depositing a cathode using evaporation deposition, wherein the cathode is disposed on the OLED material and extends under an inorganic overhang structure adjacent to each sub-pixel; and a step of depositing a encapsulation layer disposed on the cathode, wherein the encapsulation layer extends under at least a portion of the inorganic overhang structure and along sidewalls of the inorganic overhang structure.

[0005]

[0005] In another embodiment, a method of forming a device is provided. The method includes providing a substrate having an anode, adjacent pixel definition layers (PDLs) disposed on the substrate and defining sub-pixels of the device, and an inorganic overhang structure disposed on an upper surface of the PDLs; depositing an OLED material into one or more of the sub-pixels of the device using evaporation deposition; and depositing a cathode on the OLED material. In that case, the inorganic overhang structure defines a deposition angle such that both the OLED material and the cathode extend under the inorganic overhang structure.

[0006]

[0006] In yet another embodiment, a method of forming a device is provided. The method includes providing a substrate having an anode, adjacent pixel defining layer (PDL) structures disposed on the substrate and defining sub-pixels of the device, and inorganic overhang structures disposed on top of the upper surface of the PDL structures. Each inorganic overhang structure has a lower portion disposed on the upper surface of the PDL structure among the plurality of PDL structures, and an upper portion disposed on the lower portion. The upper portion includes a lower edge extending beyond the sidewall of the lower portion. An organic light emitting diode (OLED) material is disposed on the anode by evaporation. The OLED material has an OLED edge defined by the lower edge of the upper portion such that the OLED material does not contact the lower portion. A cathode is disposed on the OLED material by evaporation such that the cathode extends under the upper portion and contacts one or more of an auxiliary cathode disposed under the lower portion or a part of the sidewall of the lower portion, and has a cathode edge defined by the lower edge of the upper portion.

[0007]

[0007] To better understand the features of the present disclosure described above, the present disclosure briefly summarized above will be described more specifically with reference to embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings illustrate only exemplary embodiments and should not be considered as limiting the scope of the present disclosure, and other equally valid embodiments may be allowed.

Brief Description of the Drawings

[0008]

Figure 1A

[0008] It is a schematic cross-sectional view of a sub-pixel circuit having a progress configuration according to an embodiment.

Figure 1B

[0009] It is a schematic cross-sectional view of a sub-pixel circuit having a plug configuration according to an embodiment.

Figure 1C

[0010] It is a schematic horizontal cross-sectional view of a sub-pixel circuit having a dot type architecture according to an embodiment.

Figure 1D

[0011] It is a schematic cross-sectional view of a sub-pixel circuit having a line-type architecture according to an embodiment.

Figure 2

[0012] It is a schematic cross-sectional view of an inorganic overhang structure of a sub-pixel circuit according to an embodiment.

Figure 3

[0013] It is a flowchart of an on-demand method for forming a sub-pixel circuit according to an embodiment.

Figure 4A

[0014] Figures 4A to 4O are schematic cross-sectional views of a substrate during a method for forming a sub-pixel circuit according to an embodiment.

Figure 4B

Figure 4C

Figure 4D

Figure 4E

Figure 4F

Figure 4G

Figure 4H

Figure 4I

Figure 4J

Figure 4K

Figure 4L

Figure 4M

Figure 4N

Figure 4O

Figure 4P

[0015] Figures 4P to 4W are schematic cross-sectional views of a substrate during a method for forming a sub-pixel circuit according to an embodiment.

Figure 4Q

Figure 4R

Figure 4S

Figure 4T

Figure 4U

Figure 4V

Figure 4W

Figure 5

[0016] FIG. 1 is a flow chart of an on-demand halftone lithography method for forming a sub-pixel circuit according to an embodiment.

Figure 6

[0017] FIG. 5 is a flow chart of a one-step method for forming a sub-pixel circuit according to an embodiment.

Figure 7A

[0018] FIGS. 7A-7L are schematic cross-sectional views of a substrate during a method for forming a sub-pixel circuit according to an embodiment described herein.

Figure 7B

Figure 7C

Figure 7D

Figure 7E

Figure 7F

Figure 7G

Figure 7H

Figure 7I

Figure 7J

Figure 7K

Figure 7L

Best Mode for Carrying Out the Invention

[0009]

[0019] For ease of understanding, where possible, the same reference numbers have been used to denote the same elements common to the drawings. Even without specific description, it is considered that elements disclosed in one embodiment can be beneficially utilized in other embodiments.

[0010]

[0020] The embodiments described herein generally relate to displays. In particular, the embodiments described herein relate to sub - pixel circuits and methods for forming sub - pixel circuits that may be used in displays such as organic light - emitting diode (OLED) displays. In one embodiment that can be combined with other embodiments described herein, the display is a bottom - emission (BE) or top - emission (TE) OLED display. In another embodiment that can be combined with other embodiments described herein, the display is a passive - matrix (PM) or active - matrix (AM) OLED display.

[0011]

[0021] The first exemplary embodiment among the plurality of embodiments described in this specification includes a sub-pixel circuit having a dot-type architecture. The second exemplary embodiment among the plurality of embodiments described in this specification includes a sub-pixel circuit having a line-type architecture. The third exemplary embodiment among the plurality of embodiments described in this specification includes a sub-pixel circuit having a dot-type architecture with plugs disposed on the encapsulation layer of each sub-pixel. The fourth exemplary embodiment among the plurality of embodiments described in this specification includes a sub-pixel circuit having a line-type architecture with plugs disposed on the encapsulation layer of each sub-pixel. The fifth exemplary embodiment among the plurality of embodiments described in this specification includes an on-demand method for manufacturing one of the sub-pixel circuits of the first, second, third, or fourth exemplary embodiments. The sixth exemplary embodiment among the plurality of embodiments described in this specification includes an on-demand halftone lithography method for manufacturing one of the sub-pixel circuits of one of the first and second exemplary embodiments. The seventh exemplary embodiment among the plurality of embodiments described in this specification includes a one-step method for manufacturing one of the sub-pixel circuits of the first, second, third, or fourth exemplary embodiments.

[0012]

[0022] Each of the multiple embodiments described in this specification of the subpixel circuit (including the first to seventh exemplary embodiments) includes a plurality of subpixels, where each subpixel is defined by a permanent adjacent inorganic overhang structure in the subpixel circuit. The drawings depict two subpixels defined by adjacent inorganic overhang structures for each subpixel, but the subpixel circuits of the multiple embodiments described in this specification include a plurality of subpixels such as two or more subpixels. Each subpixel has an OLED material configured to emit white, red, green, blue, or light of other colors when powered. For example, the OLED material of the first subpixel emits red light when powered, the OLED material of the second subpixel emits green light when powered, and the OLED material of the third subpixel emits blue light when powered.

[0013]

[0023] The inorganic overhang structure is permanent in the subpixel circuit and includes an upper portion disposed at least on the lower portion. The first configuration of the inorganic overhang structure includes an upper portion of a non-conductive inorganic material and a lower portion of a conductive inorganic material. The second configuration of the inorganic overhang structure includes an upper portion of a conductive inorganic material and a lower portion of a conductive inorganic material. The third configuration of the inorganic overhang structure includes an upper portion of a non-conductive inorganic material, a lower portion of a non-conductive inorganic material, and an auxiliary cathode disposed under the lower portion. The fourth configuration of the inorganic overhang structure includes an upper portion of a conductive inorganic material, a lower portion of a non-conductive inorganic material, and an auxiliary cathode disposed under the lower portion. Any of the first, second, third, and fourth exemplary embodiments includes at least one inorganic overhang structure of the first, second, third, or fourth configuration.

[0014]

[0024] Using evaporation, adjacent inorganic overhang structures define each subpixel of a subpixel circuit of a display, thereby forming the subpixel circuit, and after the subpixel circuit is formed, the inorganic overhang structures remain in place (e.g., utilizing the fifth, sixth, or seventh exemplary embodiments). Evaporation may be utilized for the deposition of OLED materials (including a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), and an electron transport layer (ETL)), as well as for the deposition of the cathode. One or more of an encapsulation layer, a plug, and a global passivation layer may be disposed via evaporation. In a plurality of embodiments including one or more capping layers, the capping layer is disposed between the cathode and the encapsulation layer. The inorganic overhang structures define a deposition angle for each of the OLED materials and the cathode, i.e., provide a shadowing effect during evaporation. Thereby, the OLED materials do not contact the lower portions (as well as the auxiliary cathodes according to the third and fourth configurations), and the cathode contacts the lower portions according to the first and second configurations or at least the auxiliary cathodes of the third and fourth configurations. The encapsulation layer of each subpixel is disposed over the cathode such that the encapsulation layer extends under and along the sidewalls of each of at least a portion of the adjacent inorganic overhang structures.

[0015]

[0025] FIG. 1A is a schematic cross-sectional view of a subpixel circuit 100 having a progress configuration 101A. The progress configuration 101A may correspond to a first or second exemplary embodiment of the subpixel circuit 100. FIG. 1B is a schematic cross-sectional view of a subpixel circuit 100 having a plug configuration 101B. The plug configuration 101B may correspond to a third or fourth exemplary embodiment of the subpixel circuit 100. Each of the cross-sectional views of FIGS. 1A and 1B is taken along the cut line 1”-1” of FIGS. 1C and 1D.

[0016]

[0026] The sub-pixel circuit 100 includes a substrate 102. A metal layer 104 may be patterned on the substrate 102 and is defined by adjacent pixel definition layer (PDL) structures 126 disposed on the substrate 102. In one embodiment that may be combined with other embodiments described herein, the metal layer 104 is pre-patterned on the substrate 102. For example, the substrate 102 is a pre-patterned indium tin oxide (ITO) glass substrate. The metal layer 104 is configured to operate the anodes of the respective sub-pixels. The metal layer 104 includes, but is not limited to, chromium, titanium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials.

[0017]

[0027] The PDL structure 126 is disposed on the substrate 102. The PDL structure 126 includes one of an organic material, an organic material with an inorganic coating disposed thereon, or an inorganic material. The organic material of the PDL structure 126 includes, but is not limited to, polyimide. The inorganic material of the PDL structure 126 includes, but is not limited to, silicon dioxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (Si2N2O), magnesium fluoride (MgF2), or combinations thereof. Adjacent PDL structures 126 define the respective sub-pixels and expose the anodes (i.e., the metal layer 104) of the respective sub-pixels of the sub-pixel circuit 100.

[0018]

[0028] The sub-pixel circuit 100 has a plurality of sub-pixels 106 including at least a first sub-pixel 108a and a second sub-pixel 108b. The drawing depicts the first sub-pixel 108a and the second sub-pixel 108b. The sub-pixel circuit 100 of the plurality of embodiments described herein may include two or more sub-pixels 106, such as a third and a fourth sub-pixel. Each sub-pixel 106 has an OLED material 112 configured to emit white, red, green, blue, or light of another color when powered. For example, the OLED material 112 of the first sub-pixel 108a emits red light when powered, the OLED material of the second sub-pixel 108b emits green light when powered, the OLED material of the third sub-pixel emits blue light when powered, and the OLED material of the fourth sub-pixel emits another color when powered.

[0019]

[0029] The inorganic overhang structure 110 is disposed on the upper surface 103 of each of the PDL structures 126. The inorganic overhang structure 110 is permanent to the subpixel circuit. The inorganic overhang structure 110 further defines each subpixel 106 of the subpixel circuit 100. The inorganic overhang structure 110 includes an upper portion 110B disposed on at least the lower portion 110A. The first configuration of the inorganic overhang structure 110 includes an upper portion 110B of a non-conductive inorganic material and a lower portion 110A of a conductive inorganic material. The second configuration of the inorganic overhang structure 110 includes an upper portion 110B of a conductive inorganic material and a lower portion 110A of a conductive inorganic material. The third configuration of the inorganic overhang structure 110 includes an upper portion 110B of a non-conductive inorganic material, a lower portion 110A of a non-conductive inorganic material, and an auxiliary cathode 202 (shown in FIG. 2) disposed under the lower portion 110A. The fourth configuration of the inorganic overhang structure 110 includes an upper portion 110B of a conductive inorganic material, a lower portion 110A of a non-conductive inorganic material, and an auxiliary cathode 202 disposed under the lower portion 110A. The first, second, third, and fourth exemplary embodiments of the subpixel circuit 100 include at least one inorganic overhang structure 110 of the first, second, third, or fourth configuration. The inorganic overhang structure 110 can remain in place, i.e., it is permanent. Thus, organic materials from a lifted-off overhang structure that would degrade the performance of the OLED are not left behind. The elimination of the lift-off procedure also increases throughput.

[0020]

[0030] The non-conductive 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, or a combination thereof. The conductive inorganic material includes, but is not limited to, a metal-containing material. For example, the metal-containing material includes copper, titanium, aluminum, molybdenum, silver, indium tin oxide, indium zinc oxide, or a combination thereof.

[0021]

[0031] At least the lower surface 107 of the upper portion 110B is wider than the upper surface 105 of the lower portion 110A, forming an overhang 109. The lower surface 107, which is larger than the upper surface 105 forming the overhang 109, enables the upper portion 110B to shadow the lower portion 110A. Due to the shadowing of the overhang 109, each of the OLED material 112 and the cathode 114 is deposited. As further explained in the corresponding description of FIG. 2, the shadowing effect of the inorganic overhang structure 110 is the OLED angle θ of the OLED material 112 OLED (shown in FIG. 2) and the cathode angle θ of the cathode 114 cathode (shown in FIG. 2). The OLED angle θ of the OLED material 112 OLED and the cathode angle θ of the cathode 114 cathode may result from the deposition of the OLED material 112 and the cathode 114. In the first and second configurations, the OLED material 112 does not contact the lower portion 110A of the inorganic overhang structure 110, and the cathode 114 contacts the lower portion 110A of the inorganic overhang structure 110. In the third and fourth configurations, the OLED material 112 does not contact the lower portion 110A and the auxiliary cathode 202, and the cathode 114 contacts at least the auxiliary cathode 202. In another configuration, the lower portion 110A is non-conductive and the auxiliary cathode 202 is not included. In this configuration, the cathode 114 contacts a bus bar (not shown) outside the active area of the sub-pixel circuit 100.

[0022]

[0032] The OLED material 112 may include one or more of HIL, HTL, EML, and ETL. The OLED material 112 is disposed on the metal layer 104. In some embodiments that can be combined with other embodiments described herein, the OLED material 112 is disposed on the metal layer 104 and on a part of the PDL structure 126. The cathode 114 is disposed on the OLED material 112 of the PDL structure 126 within each sub-pixel 106. The cathode 114 may be disposed on a part of the sidewall 111 of the lower portion 110A. The cathode 114 and the auxiliary cathode 202 include a conductive material such as a metal. For example, the cathode 114 and / or the auxiliary cathode 202 include, but are not limited to, chromium, titanium, aluminum, ITO, or combinations thereof. In some embodiments that can be combined with other embodiments described herein, the OLED material 112 and the cathode 114 are disposed on the sidewall 113 of the upper portion 110B of the inorganic overhang structure 110. In other embodiments that can be combined with other embodiments described herein, the OLED material 112 and the cathode 114 are disposed on the upper surface 115 of the upper portion 110B of the inorganic overhang structure 110.

[0023]

[0033] Each sub-pixel 106 includes an encapsulation layer 116. The encapsulation layer 116 may be or correspond to a local passivation layer. The encapsulation layer 116 of each sub-pixel is disposed over the cathode 114 (and the OLED material 112) such that the encapsulation layer 116 extends under at least a portion of each of the inorganic overhang structures 110 and along the sidewalls of each of the inorganic overhang structures 110. The encapsulation layer 116 is disposed over the cathode 114 and over the sidewalls 111 of at least the lower portion 110A. In some embodiments that may be combined with other embodiments described herein, the encapsulation layer 116 is disposed over the sidewalls 113 of the upper portion 110B. In some embodiments that may be combined with other embodiments described herein, the encapsulation layer 116 is disposed over the upper surface 115 of the upper portion 110B of the inorganic overhang structure 110. The encapsulation layer 116 includes a non-conductive inorganic material such as a silicon-containing material. The silicon-containing material may include a Si3N4-containing material.

[0024]

[0034] In a plurality of embodiments including one or more capping layers, the capping layer is disposed between the cathode 114 and the encapsulation layer 116. For example, as shown in FIG. 1A, a first capping layer 121 and a second capping layer 123 are disposed between the cathode 114 and the encapsulation layer 116. FIG. 1A depicts a sub-pixel circuit 100 having one or more capping layers, but each of the plurality of embodiments described herein may include one or more capping layers disposed between the cathode 114 and the encapsulation layer 116. The first capping layer 121 may include an organic material. The second capping layer 123 may include an inorganic material such as lithium fluoride. The first capping layer 121 and the second capping layer 123 may be deposited by evaporation.

[0025]

[0035] The progress configuration 101A and the plug configuration 101B of the sub-pixel circuit 100 further include at least a global passivation layer 120 disposed on the inorganic overhang structure 110 and the encapsulation layer 116. The inkjet layer 118 may be disposed between the global passivation layer 120 and the inorganic overhang structure 110 and the encapsulation layer 116. The inkjet layer 118 may include an acrylic resin material. The plug configuration 101B (including the third and fourth exemplary embodiments) may include an intermediate passivation layer disposed on each plug 122 of the inorganic overhang structure 110 and the sub-pixel 106 and between the inkjet layer 118 and the global passivation layer 120.

[0026]

[0036] The plug configuration 101B, including the third and fourth exemplary embodiments, includes plugs 122 disposed on the encapsulation layer 116. Each plug 122 is disposed within a respective sub-pixel 106 of the sub-pixel circuit 100. The plug 122 may be disposed on the upper surface 115 of the upper portion 110B of the inorganic overhang structure 110. The plug 122 may have a further passivation layer disposed thereon (as shown in FIG. 4Q). The plug 122 includes, but is not limited to, a photoresist, a color filter, or a photosensitive monomer. The plug 122 has a plug transmittance that matches or substantially matches the OLED transmittance of the OLED material 112. The plugs 122 may each be of the same material and may match the OLED transmittance. The plugs 122 may be of different materials that match the OLED transmittance of each respective sub-pixel of the plurality of sub-pixels 106. By the resist transmittance and the OLED transmittance matching or substantially matching, the plug 122 can remain on the sub-pixel 106 without blocking the light emitted from the OLED material 112. The plug 122 can remain in place and thus does not require a lift-off procedure to be removed from the sub-pixel circuit 100. Since the plug 122 remains, no further pattern resist disposed on the sub-pixel 106 formed in subsequent operations is required. The lift-off procedure on the plug 122 is not required, and no further pattern resist material on the pixel circuit 100 is required, thus improving throughput.

[0027]

[0037] FIG. 1C is a schematic horizontal cross-sectional view of a sub-pixel circuit 100 having a dot type architecture 101C. The dot type architecture 101C may correspond to the first or third exemplary embodiment of the sub-pixel circuit 100. FIG. 1D is a schematic cross-sectional view of a sub-pixel circuit 100 having a line type architecture 101D. The line type architecture 101D may correspond to the second or fourth exemplary embodiment of the sub-pixel circuit 100. Each of the cross-sectional views of FIGS. 1C and 1D is taken along the cut line 1’-1’ of FIGS. 1A and 1B.

[0028]

[0038] The dot type architecture 101C includes a plurality of pixel openings 124A. Each of the pixel openings 124A is surrounded by an inorganic overhang structure 110 that defines each of the sub-pixels 106 of the dot type architecture 101C. The line type architecture 101D includes a plurality of pixel openings 124B. Each of the pixel openings 124B is adjacent to an inorganic overhang structure 110 that defines each of the sub-pixels 106 of the line type architecture 101D. Each of the on-demand method 300, the on-demand halftone lithography method 500, and the one-step method 600 for manufacturing the sub-pixel circuit 100 described herein provides the ability to manufacture both the sub-pixel circuit 100 having the dot type architecture 101C and the sub-pixel circuit 100 having the line type architecture 101D.

[0029]

[0039] FIG. 2 is a schematic cross-sectional view of the inorganic overhang structure 110 of the sub-pixel circuit 100. FIG. 2 depicts the third and fourth configurations of the inorganic overhang structure 110, but the description herein also applies to the first configuration of the inorganic overhang structure 110 including the upper portion 110B of the non-conductive inorganic material and the lower portion 110A of the conductive inorganic material, and the second configuration of the inorganic overhang structure 110 including the upper portion 110B of the conductive inorganic material and the lower portion 110A of the conductive inorganic material. In the first and second configurations, the OLED material 112 does not contact the lower portion 110A of the inorganic overhang structure 110, and the cathode 114 contacts the lower portion 110A of the inorganic overhang structure 110. In the third and fourth configurations, the OLED material 112 does not contact the lower portion 110A and the auxiliary cathode 202, and the cathode 114 contacts at least the auxiliary cathode 202.

[0030]

[0040] The upper portion 110B includes a lower edge portion 206 and an overhang vector 208. The lower edge portion 206 extends beyond the sidewall 111 of the lower portion 110A. The overhang vector 208 is defined by the lower edge portion 206 and the PDL structure 126. The OLED material 112 is disposed on the anode and on the shadow portion 210 of the PDL structure 126. The OLED material 112 forms an OLED angle θ between the OLED vector 212 and the overhang vector 208. OLED The OLED vector 212 is defined by an OLED edge portion 214 extending under the upper portion 110B and the lower edge portion 206 of the upper portion 110B. In one embodiment that can be combined with other embodiments described herein, the HIL 204 of the OLED material 112 is included. In one embodiment including the HIL 204, the OLED material 112 includes an HTL, an EML, and an ETL. The HIL 204 forms an HIL angle θ between the HIL vector 216 and the overhang vector 208. HIL The HIL vector 216 is defined by an HIL edge portion 218 extending under the upper portion 110B and the lower edge portion 206 of the upper portion 110B.

[0031]

[0041] The cathode 114 is disposed on the OLED material 112 and on the shadow portion 210 of the PDL structure 126. In some embodiments that can be combined with other embodiments described herein, the cathode 114 is disposed on a portion 220 of the sidewall 111 of the lower portion 110A. In other embodiments that can be combined with other embodiments described herein, the cathode 114 contacts a portion 222 of the auxiliary cathode 202 on the shadow portion 210 of the PDL 126. In embodiments having the cathode 114 contacting the portion 222 of the auxiliary cathode 202, the cathode 114 also contacts a portion 220 of the sidewall 111 of the lower portion 110A. The cathode 114 forms a cathode angle θ between the cathode vector 224 and the overhang vector 208. cathodeIt is formed. The cathode vector 224 is defined by a cathode edge 226 that extends at least beneath the upper portion 110B and a lower edge 206 of the upper portion 110B. The encapsulation layer 116 is disposed over the cathode 114 (and the OLED material 112) with the encapsulation layer 116 extending at least beneath the upper portion 110B of the inorganic overhang structure 110 and along the sidewall 111 of the lower portion 110A.

[0032]

[0042] During the deposition of the OLED material 112, the lower edge 206 of the upper portion 110B defines the position of the OLED edge 214. For example, the OLED material 112 evaporates at an OLED maximum angle corresponding to the OLED vector 212, and the lower edge 206 ensures that the OLED material 112 does not deposit beyond the OLED edge 214. In a plurality of embodiments having the HIL 204, the lower edge 206 of the upper portion 110B defines the position of the HIL edge 218. For example, the HIL 204 evaporates at an HIL maximum angle corresponding to the HIL vector 216, and the lower edge 206 ensures that the HIL 204 does not deposit beyond the HIL edge 218. During the deposition of the cathode 114, the lower edge 206 of the upper portion 110B defines the position of the cathode edge 226. For example, the cathode 114 evaporates at a cathode maximum angle corresponding to the cathode vector 224, and the lower edge 206 ensures that the cathode 114 does not deposit beyond the cathode edge 226. The OLED angle θ OLED is smaller than the cathode angle θ cathode The HIL angle θ HIL is smaller than the OLED angle θ OLED is smaller.

[0033]

[0043] FIG. 3 is a flowchart of an on-demand method 300 for forming sub-pixel circuit 100. The on-demand method 300 corresponds to an on-demand method for manufacturing one of the sub-pixel circuits 100 of the first, second, third, or fourth exemplary embodiments. FIGS. 4A-4O are schematic cross-sectional views of substrate 102 during method 300 for forming sub-pixel circuit 100 according to multiple embodiments described herein. FIGS. 4A-4F, 4H, 4J, 4L, and 4N correspond to the progress configuration 101A of the first or second exemplary embodiment of sub-pixel circuit 100. FIGS. 4A-4E, 4G, 4I, 4K, 4M, and 4O correspond to the plug configuration 101B of the third or fourth exemplary embodiment of sub-pixel circuit 100.

[0034]

[0044] In operation 301, as shown in FIG. 4A, lower sub-layer 402A and upper sub-layer 402B are disposed on substrate 102. Lower sub-layer 402A is disposed on PDL structure 126 and metal layer 104. Upper sub-layer 402B is disposed on lower sub-layer 402A. Lower sub-layer 402A corresponds to the lower portion 110A of inorganic overhang structure 110, and upper sub-layer 402B corresponds to the upper portion 110B of inorganic overhang structure 110. In multiple embodiments including the third and fourth configurations of inorganic overhang structure 110, auxiliary cathode layer 404 is disposed between lower sub-layer 402A and PDL structure 126 and metal layer 104.

[0035]

[0045] In operation 302, as shown in FIG. 4B, a resist 406 is disposed and patterned. The resist 406 is disposed on the upper partial layer 402B. The resist 406 is a positive resist or a negative resist. A positive resist is a part of the resist that dissolves in a resist developer when exposed to electromagnetic radiation. The resist developer is added to the resist after a pattern is written into the resist using electromagnetic radiation. A negative resist is a part of the resist that does not dissolve in a resist developer when exposed to electromagnetic radiation. The resist developer is added to the resist after a pattern is written into the resist using electromagnetic radiation. Whether the resist is a positive resist or a negative resist is determined by the chemical composition of the resist 406. The resist 406 is patterned to form one of the pixel openings 124A of the dot type architecture 101C of the first sub-pixel 108a or the pixel openings 124B of the line type architecture 101D. The patterning is one of photolithography, digital photolithography, or a laser ablation process.

[0036]

[0046] In operation 303, as shown in FIG. 4C, a portion of the upper sub-layer 402B and the lower sub-layer 402A exposed by the pixel apertures 124A, 124B is removed. The upper sub-layer 402B exposed by the pixel apertures 124A, 124B may be removed by a dry etching process. The lower sub-layer 402A exposed by the pixel apertures 124A, 124B may be removed by a wet etching process. In a plurality of embodiments including the auxiliary cathode layer 404, a portion of the auxiliary cathode layer 404 may be removed by a dry etching process or a wet etching process to form the auxiliary cathode 202 disposed under the lower portion 110A. Operation 303 forms the inorganic overhang structure 110 of the first sub-pixel 108a. Due to the etching selectivity between the material of the upper sub-layer 402B corresponding to the upper portion 110B and the material of the lower sub-layer 402A corresponding to the lower portion 110A, and the etching process for removing the exposed portions of the upper sub-layer 402B and the lower sub-layer 402A, the lower surface 107 of the upper portion 110B becomes wider than the upper surface 105 of the lower portion 110A, forming an overhang 109 (shown in FIGS. 1A, 1B, and 2). Due to the shadowing of the overhang 109, the OLED material 112 and the cathode 114 are deposited.

[0037]

[0047] In operation 304, as shown in FIG. 4D, the OLED material 112, the cathode 114, and the encapsulation layer 116 of the first sub-pixel 108a are deposited. Due to the shadowing of the overhang 109, each of the OLED material 112 and the cathode 114 is deposited. As further explained in the corresponding description of FIG. 2, the shadowing effect of the inorganic overhang structure 110 defines the OLED angle θ OLED (shown in FIG. 2) of the OLED material 112 and the cathode angle θ cathode (shown in FIG. 2) of the cathode 114. The OLED angle θ OLED of the OLED material 112 and the cathode angle θ cathodeIt is brought about by the deposition of the OLED material 112 and the cathode 114. In the first and second configurations, the OLED material 112 does not contact the lower portion 110A of the inorganic overhang structure 110, and the cathode 114 contacts the lower portion 110A of the inorganic overhang structure 110. In the third and fourth configurations, the OLED material 112 does not contact the lower portion 110A and the auxiliary cathode 202, and the cathode 114 contacts at least the auxiliary cathode 202. The encapsulation layer 116 is deposited on the cathode 114. In a plurality of embodiments including a capping layer, the capping layer is deposited between the cathode 114 and the encapsulation layer 116. The capping layer may be deposited by vapor deposition.

[0038]

[0048] In operation 305, as shown in FIG. 4E, a resist 408 is formed within a well 410 of the first sub-pixel 108a. In operation 306, as shown in FIGS. 4F and 4G, the encapsulation layer 116, the cathode 114, and the OLED layer 112 exposed by the resist 408 are removed. The encapsulation layer 116, the cathode 114, and the OLED material 112 exposed by the resist 408 may be removed by a wet etching process. According to a plurality of embodiments having the plug configuration 101A of the sub-pixel circuit 100, as shown in FIG. 4F, the resist 408 is removed. According to a plurality of embodiments having the plug configuration 101B of the sub-pixel circuit 100, as shown in FIG. 4G, the resist 408 corresponds to a plug 122 of the first sub-pixel 108a. In operation 307, as shown in FIGS. 4H and 4I, a resist 412 is disposed and patterned. The resist 412 is disposed on the upper sub-layer 402B and the upper portion 110B of the first sub-pixel 108a. In a plurality of embodiments having the plug configuration 101B, as shown in FIG. 4I, a passivation layer 414 is disposed at least on the plug 122 of the first sub-pixel 108a. The passivation layer 414 of the plug configuration 101B may be disposed on the upper sub-layer 402B and the upper portion 110B of the first sub-pixel 108a. The resist 412 is patterned to form one of the pixel openings 124A of the dot type architecture 101C or the pixel openings 124B of the line type architecture 101D of the second sub-pixel 108b.

[0039]

[0049] In operation 308, a part of the upper partial layer 402B and the lower partial layer 402A exposed by the pixel openings 124A and 124B of the second sub-pixel 108b is removed. The upper partial layer 402B exposed by the pixel openings 124A and 124B may be removed by a dry etching process. The lower partial layer 402A exposed by the pixel openings 124A and 124B may be removed by a wet etching process. In a plurality of embodiments including the auxiliary cathode layer 404, a part of the auxiliary cathode 404 may be removed by a dry etching process or a wet etching process to form the auxiliary cathode 202 disposed under the lower part 110A. Operation 308 forms the inorganic overhang structure 110 of the second sub-pixel 108b. Due to the etching selectivity between the material of the upper partial layer 402B corresponding to the upper part 110B and the material of the lower partial layer 402A corresponding to the lower part 110A, and the etching process for removing the exposed portions of the upper partial layer 402B and the lower partial layer 402A, the lower surface 107 of the upper part 110B becomes wider than the upper surface 105 of the lower part 110A, forming the overhang 109 (shown in FIGS. 1A, 1B, and 2). Due to the shadowing of the overhang 109, the OLED material 112 and the cathode 114 are deposited.

[0040]

[0050] In operation 309, as shown in FIGS. 4J and 4K, the OLED material 112, the cathode 114, and the encapsulation layer 116 of the second sub-pixel 108b are deposited. In a plurality of embodiments including a capping layer, the capping layer is deposited between the cathode 114 and the encapsulation layer 116. The capping layer may be deposited by evaporation. Due to the shadowing of the overhang 109, each of the OLED material 112 and the cathode 114 is deposited. As further described in the corresponding description of FIG. 2, the shadowing effect of the inorganic overhang structure 110 defines the OLED angle θ OLED (shown in FIG. 2) of the OLED material 112 and the cathode angle θ cathode (shown in FIG. 2) of the cathode 114. The OLED angle θ OLEDand the cathode angle θ of the cathode 114 cathode results from the deposition of the OLED material 112 and the cathode 114. In the first and second configurations, the OLED material 112 does not contact the lower portion 110A of the inorganic overhang structure 110, and the cathode 114 contacts the lower portion 110A of the inorganic overhang structure 110. In the third and fourth configurations, the OLED material 112 does not contact the lower portion 110A and the auxiliary cathode 202, and the cathode 114 contacts at least the auxiliary cathode 202. The encapsulation layer 116 is deposited on the cathode 114.

[0041]

[0051] In operation 310, as shown in FIGS. 4L and 4M, a resist 416 is formed within the well 418 of the second subpixel 108b. In operation 311, as shown in FIGS. 4N and 4O, the encapsulation layer 116, the cathode 114, and the OLED material 112 exposed by the resist 416 are removed. The encapsulation layer 116, the cathode 114, and the OLED material 112 exposed by the resist 416 may be removed by a wet etching process. According to a plurality of embodiments having the plug-in configuration 101A of the subpixel circuit 100, as shown in FIG. 4F, the resist 416 is removed. According to a plurality of embodiments having the plug configuration 101B of the subpixel circuit 100, as shown in FIGS. 4G and 4O, the resist 416 corresponds to the plug 122 of the second subpixel 108b. The operations 301 to 311 described herein form a subpixel circuit 100 including two subpixels 106. Operations 306 to 310 may be repeated for each additional subpixel, for example, for the third and / or fourth subpixels.

[0042]

[0052] FIG. 5 is a flowchart of an on-demand halftone lithography method 500 for forming the sub-pixel circuit 100. The on-demand halftone lithography method 500 corresponds to an on-demand halftone lithography method for manufacturing the sub-pixel circuit 100 of one of the first and second exemplary embodiments. FIGS. 4A-4D and FIGS. 4P-4W are schematic cross-sectional views of a substrate 102 during the method 500 for forming the sub-pixel circuit 100 according to a plurality of embodiments described herein.

[0043]

[0053] In operation 501, as shown in FIG. 4A, a lower sub-layer 402A and an upper sub-layer 402B are disposed on the substrate 102. The lower sub-layer 402A is disposed on the PDL structure 126 and the metal layer 104. The upper sub-layer 402B is disposed on the lower sub-layer 402A. The lower sub-layer 402A corresponds to the lower portion 110A of the inorganic overhang structure 110, and the upper sub-layer 402B corresponds to the upper portion 110B of the inorganic overhang structure 110. In a plurality of embodiments including the third and fourth configurations of the inorganic overhang structure 110, an auxiliary cathode layer 404 is disposed between the lower sub-layer 402A and the PDL structure 126 and the metal layer 104.

[0044]

[0054] In operation 502, as shown in FIG. 4B, resist 406 is disposed and patterned. Resist 406 is disposed on the upper partial layer 402B. Resist 406 is a positive resist or a negative resist. A positive resist is a part of the resist that dissolves in a resist developer respectively when exposed to electromagnetic radiation. The resist developer is added to the resist after a pattern is written into the resist using electromagnetic radiation. A negative resist is a part of the resist that does not dissolve in a resist developer respectively when exposed to electromagnetic radiation. The resist developer is added to the resist after a pattern is written into the resist using electromagnetic radiation. Whether the resist is a positive resist or a negative resist is determined by the chemical composition of resist 406. Resist 406 is patterned to form one of pixel openings 124A of dot type architecture 101C of the first sub-pixel 108a or pixel openings 124B of line type architecture 101D. The patterning is one of photolithography, digital photolithography, or a laser ablation process.

[0045]

[0055] In operation 503, as shown in FIG. 4C, a portion of the upper sub-layer 402B and the lower sub-layer 402A exposed by the pixel openings 124A and 124B is removed. The upper sub-layer 402B exposed by the pixel openings 124A and 124B may be removed by a dry etching process. The lower sub-layer 402A exposed by the pixel openings 124A and 124B may be removed by a wet etching process. In a plurality of embodiments including the auxiliary cathode layer 404, a portion of the auxiliary cathode 404 may be removed by a dry etching process or a wet etching process to form the auxiliary cathode 202 disposed under the lower portion 110A. Operation 503 forms the inorganic overhang structure 110 of the first sub-pixel 108a. Due to the etching selectivity between the material of the upper sub-layer 402B corresponding to the upper portion 110B and the material of the lower sub-layer 402A corresponding to the lower portion 110A, and the etching process for removing the exposed portions of the upper sub-layer 402B and the lower sub-layer 402A, the lower surface 107 of the upper portion 110B becomes wider than the upper surface 105 of the lower portion 110A, forming an overhang 109 (shown in FIGS. 1A, 1B, and 2). Due to the shadowing of the overhang 109, the OLED material 112 and the cathode 114 are deposited.

[0046]

[0056] In operation 504, as shown in FIG. 4D, the OLED material 112, the cathode 114, and the encapsulation layer 116 of the first sub-pixel 108a are deposited. In a plurality of embodiments including a capping layer, the capping layer is deposited between the cathode 114 and the encapsulation layer 116. The capping layer may be deposited by evaporation. Due to the shadowing of the overhang 109, each of the OLED material 112 and the cathode 114 is deposited. As further explained in the corresponding description of FIG. 2, the shadowing effect of the inorganic overhang structure 110 defines the OLED angle θ OLED (shown in FIG. 2) of the OLED material 112 and the cathode angle θ cathode (shown in FIG. 2) of the cathode 114. The OLED angle θ OLEDand the cathode angle θ of the cathode 114 cathode results from the deposition of the OLED material 112 and the cathode 114. In the first and second configurations, the OLED material 112 does not contact the lower portion 110A of the inorganic overhang structure 110, and the cathode 114 contacts the lower portion 110A of the inorganic overhang structure 110. In the third and fourth configurations, the OLED material 112 does not contact the lower portion 110A and the auxiliary cathode 202, and the cathode 114 contacts at least the auxiliary cathode 202. The encapsulation layer 116 is deposited on the cathode 114.

[0047]

[0057] In operation 505, as shown in FIG. 4P, the resist 420 is disposed and halftone patterned. Halftone patterning the resist 420 includes a digital lithography process of patterning the resist to form two or more portions. Each of the two or more portions has a different depth. Each portion corresponds to a respective subpixel. As shown in FIG. 4P, by the halftone patterning of the resist 420, a first portion 422 is formed over the first subpixel 108a and a second portion 424 is formed over the second subpixel 108b. The second portion 424 exposes a part of the pixel openings 124A, 124B of the second subpixel 108b. In operation 506, as shown in FIG. 4Q, the encapsulation layer 116, the cathode 114, the OLED material 112, the upper portion layer 402B, and the lower portion layer 402A exposed by the pixel openings 124A, 124B are removed. Operation 506 forms the inorganic overhang structure 110 of the second subpixel 108b. Due to the etching selectivity between the material of the upper portion layer 402B corresponding to the upper portion 110B and the material of the lower portion layer 402A corresponding to the lower portion 110A, and the etching process of removing the exposed portions of the upper portion layer 402B and the lower portion layer 402A, the lower surface 107 of the upper portion 110B becomes wider than the upper surface 105 of the lower portion 110A, forming an overhang 109 (shown in FIGS. 1A, 1B, and 2). Due to the shadowing of the overhang 109, the OLED material 112 and the cathode 114 are deposited.

[0048]

[0058] In operation 507, as shown in FIG. 4R, the resist 420 is removed. In operation 508, as shown in FIG. 4S, the OLED material 112, the cathode 114, and the encapsulation layer 116 of the second sub-pixel 108b are deposited. In a plurality of embodiments including a capping layer, the capping layer is deposited between the cathode 114 and the encapsulation layer 116. The capping layer may be deposited by evaporation. Due to the shadowing of the overhang 109, each of the OLED material 112 and the cathode 114 is deposited. As further explained in the corresponding description of FIG. 2, the shadowing effect of the inorganic overhang structure 110 defines the OLED angle θ of the OLED material 112 OLED (shown in FIG. 2) and the cathode angle θ of the cathode 114 cathode (shown in FIG. 2). The OLED angle θ of the OLED material 112 OLED and the cathode angle θ of the cathode 114 cathode result from the deposition of the OLED material 112 and the cathode 114. In the first and second configurations, the OLED material 112 does not contact the lower portion 110A of the inorganic overhang structure 110, and the cathode 114 contacts the lower portion 110A of the inorganic overhang structure 110. In the third and fourth configurations, the OLED material 112 does not contact the lower portion 110A and the auxiliary cathode 202, and the cathode 114 contacts at least the auxiliary cathode 202. The encapsulation layer 116 is deposited on the cathode 114.

[0049]

[0059] In operation 509, as shown in FIG. 4T, the resist 426 is disposed and halftone patterned. Halftone patterning the resist 426 includes a digital lithography process of patterning the resist to form two or more portions. Each of the two or more portions has a different depth. Each portion corresponds to a respective subpixel. As shown in FIG. 4U, due to the halftone patterning of the resist 426, a first portion 422 is formed over the first subpixel 108a and a second portion 424 is formed over the second subpixel 108b. In operation 510, as shown in FIG. 4V, the first portion 422 of the resist 426 is plasma ashed. In operation 511, as shown in FIG. 4W, the encapsulation layer 116, the cathode 114, and the OLED material 112 of the second subpixel 108b that are exposed by the resist 426 are removed. In operation 512, as shown in FIG. 4Y, the resist 426 is removed. Operations 501-512 described herein form a subpixel circuit 100 including two subpixels 106. Operations 505-512 may be repeated for each additional subpixel, e.g., for the third and / or fourth subpixels.

[0050]

[0060] FIG. 6 is a flowchart of a one-step method 600 for forming the subpixel circuit 100. The one-step method 600 corresponds to a one-step method for manufacturing one of the subpixel circuits 100 of the first, second, third, or fourth exemplary embodiments. FIGS. 7A-7L are schematic cross-sectional views of a substrate 102 during the method 600 for forming the subpixel circuit 100 according to a plurality of embodiments described herein. FIGS. 7A-7C, 7E, 7G, 7I, and 7K correspond to a progress configuration 101A of the first or second exemplary embodiment of the subpixel circuit 100. FIGS. 7A, 7B, 7D, 7F, 7H, 7J, and 7L correspond to a plug configuration 101B of the third or fourth exemplary embodiment of the subpixel circuit 100.

[0051]

[0061] In operation 601, as shown in FIG. 7A, an inorganic overhang structure 110 is formed. Forming the inorganic overhang structure 110 includes disposing a lower sub-layer and an upper sub-layer on the substrate 102. The first lower portion is disposed on the PDL structure 126 and the metal layer 104. The upper sub-layer is disposed on the lower sub-layer. The lower sub-layer corresponds to the lower portion 110A of the inorganic overhang structure 110, and the upper sub-layer corresponds to the upper portion 110B of the inorganic overhang structure 110. In a plurality of embodiments including the third and fourth configurations of the inorganic overhang structure 110, an auxiliary cathode layer is disposed between the lower sub-layer 402A and the PDL structure 126 and the metal layer 104. The auxiliary cathode layer corresponds to the auxiliary cathode 202. A resist is disposed on the upper sub-layer and patterned. To form the inorganic overhang structure 110, a portion of the upper sub-layer 402B and the lower sub-layer 402A exposed by the pixel openings 124A, 124B is removed.

[0052]

[0062] In operation 602, as shown in FIG. 7B, the OLED material 112, the cathode 114, and the encapsulation layer 116 of the first sub-pixel 108a are deposited. In a plurality of embodiments including a capping layer, the capping layer is deposited between the cathode 114 and the encapsulation layer 116. The capping layer may be deposited by evaporation. As further described in the corresponding description of FIG. 2, the shadowing effect of the inorganic overhang structure 110 defines the OLED angle θ OLED (shown in FIG. 2) of the OLED material 112 and the cathode angle θ cathode (shown in FIG. 2) of the cathode 114. The OLED angle θ OLED of the OLED material 112 and the cathode angle θ cathodeIt results from the deposition of the OLED material 112 and the cathode 114. In the first and second configurations, the OLED material 112 does not contact the lower portion 110A of the inorganic overhang structure 110, and the cathode 114 contacts the lower portion 110A of the inorganic overhang structure 110. In the third and fourth configurations, the OLED material 112 does not contact the lower portion 110A and the auxiliary cathode 202, and the cathode 114 contacts at least the auxiliary cathode 202. The encapsulation layer 116 is deposited on the cathode 114.

[0053]

[0063] In operation 603, as shown in FIG. 7C, a resist 702 is formed within a well 704 of the first sub-pixel 108a. In operation 604, as shown in FIGS. 7E and 7F, the encapsulation layer 116, the cathode 114, and the OLED layer 112 exposed by the resist 702 are removed. The encapsulation layer 116, the cathode 114, and the OLED material 112 exposed by the resist 702 may be removed by a wet etching process. According to a plurality of embodiments having the plug-in configuration 101A of the sub-pixel circuit 100, as shown in FIG. 7E, the resist 408 is removed. According to a plurality of embodiments having the plug configuration 101B of the sub-pixel circuit 100, as shown in FIGS. 7D and 7F, the resist 702 corresponds to a plug 122 of the first sub-pixel 108a.

[0054]

[0064] In operation 605, as shown in FIGS. 7G and 7H, the OLED material 112, the cathode 114, and the encapsulation layer 116 of the second sub-pixel 108b are deposited. In a plurality of embodiments including a capping layer, the capping layer is deposited between the cathode 114 and the encapsulation layer 116. The capping layer may be deposited by evaporation. Due to the shadowing of the overhang 109, each of the OLED material 112 and the cathode 114 is deposited. As further explained in the corresponding description of FIG. 2, the shadowing effect of the inorganic overhang structure 110 is the OLED angle θ of the OLED material 112 OLED (shown in FIG. 2) and the cathode angle θ of the cathode 114cathode (shown in FIG. 2) and define the OLED angle θ of the OLED material 112 OLED and the cathode angle θ of the cathode 114 cathode result from the deposition of the OLED material 112 and the cathode 114. In the first and second configurations, the OLED material 112 does not contact the lower portion 110A of the inorganic overhang structure 110, and the cathode 114 contacts the lower portion 110A of the inorganic overhang structure 110. In the third and fourth configurations, the OLED material 112 does not contact the lower portion 110A and the auxiliary cathode 202, and the cathode 114 contacts at least the auxiliary cathode 202. The encapsulation layer 116 is deposited on the cathode 114.

[0055]

[0065] In operation 606, as shown in FIG. 7L, a resist 704 is formed within the well 706 of the second sub-pixel 108b. In operation 607, as shown in FIGS. 7K and 7L, the encapsulation layer 116, the cathode 114, and the OLED material 112 exposed by the resist 416 are removed. The encapsulation layer 116, the cathode 114, and the OLED material 112 exposed by the resist 706 may be removed by a wet etching process. According to a plurality of embodiments having the progress configuration 101A of the sub-pixel circuit 100, as shown in FIG. 7K, the resist 706 is removed. According to a plurality of embodiments having the plug configuration 101B of the sub-pixel circuit 100, as shown in FIGS. 7J and 7L, the resist 706 corresponds to the plug 122 of the second sub-pixel 108b. The operations 601-607 described herein form a sub-pixel circuit 100 including two or more sub-pixels 106. Operations 605-607 may be repeated for each additional sub-pixel, for example, for the third and / or fourth sub-pixels.

[0056]

[0066] In summary, the embodiments described in this specification relate to sub-pixel circuits and methods of forming sub-pixel circuits that may be used in displays such as organic light-emitting diode (OLED) displays. Using evaporation, adjacent inorganic overhang structures define each sub-pixel of a sub-pixel circuit of a display, thereby forming the sub-pixel circuit, and after the sub-pixel circuit is formed, the inorganic overhang structures remain in place (e.g., utilizing the fifth, sixth, or seventh exemplary embodiments). Evaporation may be utilized for the deposition of OLED materials and cathodes. The inorganic overhang structures define a deposition angle for each of the OLED materials and cathodes, i.e., provide a shadowing effect during evaporation. Thereby, the OLED materials do not contact the lower portions (and the auxiliary cathodes according to the third and fourth configurations), and the cathodes contact the lower portions according to the first and second configurations or at least the auxiliary cathodes of the third and fourth configurations. The encapsulation layer of each sub-pixel is disposed over the cathode such that the encapsulation layer extends under and along the sidewalls of at least a portion of each adjacent inorganic overhang structure.

[0057]

[0067] The foregoing description has been directed to embodiments of the present disclosure, but other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof, and the scope of the present disclosure is defined by the following claims.

Claims

**Claim 1** A device comprising a plurality of sub-pixels, wherein each sub-pixel of the plurality of sub-pixels is defined by an adjacent pixel definition layer (PDL) structure with an inorganic overhang structure disposed on the PDL structure, and each sub-pixel has an anode, an organic light-emitting diode (OLED) material disposed on the anode, and a cathode disposed on the OLED material, and the device is fabricated by a process comprising a plurality of steps, the plurality of steps being a step of depositing the OLED material on a substrate using evaporation, wherein the OLED material is disposed on and in contact with the anode, a step of depositing a cathode using evaporation, wherein the cathode is disposed on the OLED material and extends under the inorganic overhang structure adjacent to each sub-pixel, and a step of depositing an encapsulation layer disposed on the cathode, wherein the encapsulation layer extends under at least a portion of the inorganic overhang structure and along sidewalls of the inorganic overhang structure. A device. **Claim 2** Each of the inorganic overhang structures is a lower portion disposed on an upper surface of one of the PDL structures of the PDL structures, and an upper portion disposed on the lower portion, the upper portion comprising a lower edge extending beyond a sidewall of the lower portion. The device according to claim 1. **Claim 3** Each of the inorganic overhang structures is the upper portion of a non-conductive inorganic material and the lower portion of a conductive inorganic material, the upper portion of the conductive inorganic material and the lower portion of the conductive inorganic material, the upper portion of the non-conductive inorganic material, the lower portion of the non-conductive inorganic material, and an auxiliary cathode disposed under the lower portion, or the upper portion of the conductive inorganic material, the lower portion of the non-conductive inorganic material, and the auxiliary cathode disposed under the lower portion. The device according to claim 2, comprising one of the above. **Claim 4** The cathode extends under the portion of the inorganic overhang structure and contacts one or more of the auxiliary cathode or a part of the lower portion. The device according to claim 3. **Claim 5** So that the OLED material does not contact the lower portion or the auxiliary cathode, the OLED material is defined by the lower edge of the upper portion, The device according to claim 4, wherein the cathode is defined by the lower edge of the upper portion.

6. The non-conductive inorganic material includes an inorganic silicon-containing material, The device according to claim 3, wherein the conductive inorganic material includes a metal-containing material.

7. Each sub-pixel further includes a plug disposed on the encapsulation layer, and the plug has a plug transmittance that matches or substantially matches the OLED transmittance of the OLED material. The device according to claim 1.

8. The device according to claim 7, wherein the plug includes a photoresist, a color filter, or a photosensitive monomer material.

9. The device according to claim 1, wherein the device has a dot type architecture or a line type architecture.

10. The device according to claim 1, wherein the substrate is a pre-patterned indium tin oxide (ITO) glass substrate.

11. The device according to claim 1, wherein the OLED material includes a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), and an electron transport layer (ETL).

12. The device according to claim 1, further including a global passivation layer disposed on the inorganic overhang structure and the encapsulation layer.

13. A method of forming a device, comprising: Providing a substrate, wherein the substrate An anode, Adjacent pixel defining layer (PDL) structures disposed on the substrate and defining sub-pixels of the device, and Providing a substrate having an inorganic overhang structure disposed on the upper surface of the PDL structure, Depositing an OLED material into one or more of the sub-pixels of the device using evaporation, and Depositing a cathode on the OLED material, wherein the inorganic overhang structure defines a deposition angle such that both the OLED material and the cathode extend under the inorganic overhang structure.

14. Each of the inorganic overhang structures A lower portion disposed on the upper surface of one of the PDL structures of the PDL structure, and The method according to claim 13, comprising an upper portion disposed on the lower portion, the upper portion including a lower edge extending beyond the sidewall of the lower portion.

15. Each of the inorganic overhang structures the upper portion of the non-conductive inorganic material and the lower portion of the conductive inorganic material, the upper portion of the conductive inorganic material and the lower portion of the conductive inorganic material, the upper portion of the non-conductive inorganic material, the lower portion of the non-conductive inorganic material, and an auxiliary cathode disposed under the lower portion, or The method according to claim 14, comprising one of the upper portion of the conductive inorganic material, the lower portion of the non-conductive inorganic material, and the auxiliary cathode disposed under the lower portion.

16. The OLED material is defined by the lower edge of the upper portion so that the OLED material does not contact the lower portion or the auxiliary cathode. The method according to claim 15, wherein the cathode is defined by the lower edge of the upper portion.

17. The method according to claim 14, further comprising disposing the OLED material, the cathode, and the encapsulation layer on the sidewall of the upper portion.

18. The method according to claim 13, further comprising disposing a global passivation layer on the inorganic overhang structure and the encapsulation layer.

19. A method of forming a device, providing a substrate, the substrate comprising an anode, adjacent pixel definition layer (PDL) structures disposed on the substrate and defining sub-pixels of the device, and an inorganic overhang structure disposed on the upper surface of the PDL structure, each inorganic overhang structure comprising a lower portion disposed on the upper surface of one of the PDL structures, and providing a substrate having an upper portion disposed on the lower portion, the upper portion including a lower edge extending beyond the sidewall of the lower portion. depositing an organic light-emitting diode (OLED) material on the anode, the OLED material having an OLED edge defined by the lower edge of the upper portion so that the OLED material does not contact the lower portion. Depositing a cathode disposed on the OLED material, the cathode having a cathode edge defined by the lower edge of the upper portion, extending under the upper portion, and contacting one or more of an auxiliary cathode disposed under the lower portion or a part of the side wall of the lower portion.

20. The method according to claim 19, wherein both the OLED material and the cathode extend under the inorganic overhang structure, and the inorganic overhang structure defines a deposition angle.

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