OLED structure and process based on pixel passivation by removing the OLED stack above the heat absorbing structure

Abstract

A device including a subpixel circuit and a method for forming the subpixel circuit may be utilized in a display such as an organic light-emitting diode (OLED) display. In one example, the device includes a substrate, a plurality of pixel-defining layer (PDL) structures disposed on the substrate, each PDL structure having an upper PDL surface, and a plurality of heat-absorbing structures disposed on the upper PDL surfaces of the plurality of PDL structures. Each adjacent heat-absorbing structure includes a top surface and two sidewalls. The adjacent heat-absorbing structures define subpixels of the device, each subpixel including an anode, an OLED material disposed on the anode, a cathode disposed on the OLED material, and an encapsulation layer disposed on the cathode and on a first portion of the top surface of the first heat-absorbing structure and a second portion of the top surface of the second heat-absorbing structure.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 483,123, filed February 3, 2023, which is incorporated herein by reference.

[0002] FIELD OF THE INVENTION The embodiments described herein relate generally to displays. More particularly, the embodiments described herein relate to subpixel circuits that may be utilized in displays such as organic light emitting diode (OLED) displays. [Background technology]

[0003] Input devices that include display devices may be used in a variety of electronic systems. Organic light-emitting diodes (OLEDs) are light-emitting diodes (LEDs) in which a light-emitting electroluminescent layer is a film of organic compounds that emits light in response to an electric current. OLEDs are used to fabricate the display devices in many of today's electronic devices. Today's electronics manufacturers are driving these display devices to shrink in size while at the same time providing higher resolution than was possible just a few years ago.

[0004] OLED pixel patterning is currently based on processes that limit panel size, pixel resolution, and substrate size. Photolithography should be used to pattern pixels, rather than utilizing fine metal masks. Currently, OLED pixel patterning requires lifting off the organic material after the patterning process. Lifting off the organic material introduces particle issues that impair OLED performance. Therefore, there is a need in the art for subpixel circuits that can increase the number of pixels per inch and improve OLED performance. Summary of the Invention

[0005] In one embodiment, a device is provided that includes a substrate, a plurality of pixel definition layer (PDL) structures disposed over the substrate, each PDL structure having an upper PDL surface, and a plurality of heat absorbing structures disposed on the upper PDL surfaces of the plurality of PDL structures, each adjacent heat absorbing structure including a top surface and two sidewalls. Adjacent heat absorbing structures define subpixels of the device, each subpixel including an anode, an organic light emitting diode (OLED) material disposed over the anode, the OLED material having a first OLED terminal in contact with a first sidewall of the first heat absorbing structure and a second OLED terminal in contact with a second sidewall of the second heat absorbing structure, a cathode disposed over the OLED material, the cathode having a first cathode terminal in contact with the first sidewall of the first heat absorbing structure and a second cathode terminal in contact with the second sidewall of the second heat absorbing structure, and an encapsulation layer disposed over the cathode and over a first portion of a top surface of the first heat absorbing structure and a second portion of a top surface of the second heat absorbing structure.

[0006] In another embodiment, a device is provided that includes a substrate and a plurality of heat absorbing structures disposed on the substrate, each heat absorbing structure having a top surface and two sidewalls, the heat absorbing structures defining a plurality of subpixels, each subpixel comprising an anode, an organic light emitting diode (OLED) material disposed on the anode, the OLED material extending along a first sidewall of a first heat absorbing structure and in contact with the top surface of the first heat absorbing structure at a first OLED edge, and extending along a second sidewall of a second heat absorbing structure and in contact with the top surface of the second heat absorbing structure at a second OLED edge, and a second OLED material disposed on the OLED material. a cathode disposed over the first heat absorbing structure, the cathode extending along a first sidewall of the first heat absorbing structure and in contact with the top surface of the first heat absorbing structure at a first cathode end point and extending along a second sidewall of the second heat absorbing structure and in contact with the top surface of the second heat absorbing structure at a second cathode end point; and an encapsulation layer disposed over the cathode, the encapsulation layer in contact with a first portion of the top surface of the first heat absorbing structure and in contact with a second portion of the top surface of the second heat absorbing structure.

[0007] In another embodiment, a method is provided that includes disposing a first OLED material in a first pixel opening over an anode, in a second pixel opening, and on top surfaces of multiple adjacent heat absorbing structures disposed on an upper PDL surface of a pixel-defining layer (PDL) structure, the first pixel opening and the second pixel opening being defined by adjacent heat absorbing structures of the multiple adjacent heat absorbing structures, disposing a cathode over the first OLED material, removing the first OLED material and the cathode from the top surfaces of the multiple adjacent heat absorbing structures, depositing an encapsulation layer over the cathode and from the top surfaces of the multiple adjacent heat absorbing structures, forming a photoresist over the encapsulation layer in the first pixel opening and on a first portion of the top surface of the first heat absorbing structure and a second portion of the top surface of the second heat absorbing structure, and removing the encapsulation layer exposed by the photoresist.

[0008] In another embodiment, a method is provided that includes disposing a first OLED material in a first pixel opening over an anode, in a second pixel opening, and on top surfaces of a plurality of adjacent heat absorbing structures disposed on an upper PDL surface of a pixel defining layer (PDL) structure, the first pixel opening and the second pixel opening being defined by adjacent heat absorbing structures of the plurality of adjacent heat absorbing structures; removing the first OLED material on the top surfaces of the plurality of adjacent heat absorbing structures; and removing the first OLED material from the top surfaces of the plurality of adjacent heat absorbing structures. disposing a cathode over the material and over the top surfaces of the plurality of adjacent heat absorbing structures; depositing an encapsulation layer over the cathode; forming photoresist over the encapsulation layer in the first pixel opening and over a first portion of the top surface of the first heat absorbing structure and a second portion of the top surface of the second heat absorbing structure; and removing the encapsulation layer and the cathode over the first portion of the top surface of the first heat absorbing structure and the second portion of the top surface of the second heat absorbing structure exposed by the photoresist.

[0009] 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, in a manner that allows the above-listed features of the disclosure to be understood in detail. It should be noted, however, that the accompanying drawings depict only exemplary embodiments and, therefore, should not be considered as limiting the scope of the embodiments, which may embrace other equally effective embodiments. [Brief explanation of the drawings]

[0010] [Figure 1A] 1 is a schematic cross-sectional view of a sub-pixel circuit according to an embodiment. [Figure 1B] 1 is a schematic cross-sectional view of a sub-pixel circuit according to an embodiment. [Figure 1C] FIG. 2 is a top cross-sectional view of a subpixel circuit according to an embodiment. [Figure 2] 1 is a flow diagram of a method for forming a sub-pixel circuit according to an embodiment. [Figures 3A-3E] 1A-1C are schematic cross-sectional views of a portion of a substrate during a method of forming a subpixel circuit according to an embodiment. [Figure 4] 1 is a flow diagram of a method for forming a sub-pixel circuit according to an embodiment. [Figures 5A-5E] 1A-1C are schematic cross-sectional views of a portion of a substrate during a method of forming an OLED pixel structure according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] For ease of understanding, where 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.

[0012] FIELD OF THE INVENTION The embodiments described herein relate generally to displays. More particularly, the embodiments described herein 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.

[0013] 1A is a schematic cross-sectional view of a subpixel circuit 100A. The cross-sectional view of FIG. 1A is taken along section line 1"-1" in FIG. 1C.

[0014] The subpixel circuit 100A includes a substrate 102. A metal-containing layer 104 may be patterned on the substrate 102, and the metal-containing layer 104 is defined by adjacent pixel-defining layer (PDL) structures 126 disposed on the substrate 102. In one embodiment, the metal-containing 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-containing layer 104 is configured to act as the anode for each subpixel. The metal-containing layer 104 may include, but is not limited to, chromium, titanium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials.

[0015] The PDL structure 126 is disposed on the substrate 102. The PDL structure includes an upper PDL surface 127A coupled to a first PDL sidewall 127B and a second PDL sidewall 127C. Both the first PDL sidewall 127B and the second PDL sidewall 127C have tapered edges. The PDL structure 126 includes one of an organic material, an organic material having 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 oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiNO), magnesium fluoride (MgF), or a combination thereof. Adjacent PDL structures 126 define respective subpixels 106 and expose the anode (ie, metal-containing layer 104) of each subpixel 106 of the subpixel circuit 100A.

[0016] The subpixel circuit 100A has adjacent heat absorbing structures 121, including a first heat absorbing structure 121A and a second heat absorbing structure 121B. The heat absorbing structure 121 is disposed on the upper PDL surface 127A of the PDL structure 126. The heat absorbing structure 121 includes a top surface 122A coupled to a first sidewall 122B and a second sidewall 122C. Both the first sidewall 122B and the second sidewall 122C have reverse tapered edges. The heat absorbing structure 121 absorbs energy and generates heat. The generated heat is localized to the heat absorbing structure 121. This localized heating of the heat absorbing structure 121 removes material disposed on the top surface 122A of the heat absorbing structure 121. This material may be organic light emitting diode (OLED) material 112, or in some embodiments, the cathode 114. This material may be removed by evaporation. In some embodiments, the heat absorbing structure 121 comprises a metal layer. The metal layer includes, but is not limited to, molybdenum or titanium. In some embodiments, the heat absorbing structure 121 comprises a multi-layer structure. The multi-layer structure may include a metal layer, a transparent layer, and another metal layer. The metal layer includes, but is not limited to, molybdenum or titanium. The transparent layer includes, but is not limited to, silicon oxide (SiO2) or silicon nitride (SiN x ) is included.

[0017] The subpixel circuit 100A includes at least a first subpixel 108A and a second subpixel 108B. While the figure shows a first subpixel 108A and a second subpixel 108B, the subpixel circuit 100A of the embodiments described herein may include more than two subpixels 106, such as a third and fourth subpixel. Each subpixel 106 has an OLED material 112 configured to emit white, red, green, blue, or other color light when energized. For example, the OLED material 112 of the first subpixel 108A emits red light when energized, the OLED material 112 of the second subpixel 108B emits green light when energized, the OLED material 112 of the third subpixel emits blue light when energized, and the OLED material 112 of the fourth and fifth subpixels emit light of another color when energized. The OLED material 112 is different from the material of the PDL structure 126 .

[0018] OLED material 112 is disposed on metal-containing layer 104. OLED material 112 has a first OLED end 112A of OLED material 112 in contact with a first sidewall 122B of first heat absorbing structure 121A. OLED material 112 has a second OLED end 112B in contact with a second sidewall 122C of second heat absorbing structure 121B. OLED material 112 is disposed on PDL structure 126. OLED material 112 is disposed on a first PDL sidewall 127B of first PDL structure 126A on an upper PDL surface 127A of first PDL structure 126A. In some embodiments, OLED material 112 is in contact with first PDL sidewall 127B and upper PDL surface 127A of first PDL structure 126A. OLED material 112 is disposed on second PDL sidewall 127C of second PDL structure 126B on top PDL surface 127A of second PDL structure 126B. In some embodiments, OLED material 112 is in contact with second PDL sidewall 127C and top PDL surface 127A of second PDL structure 126B.

[0019] The cathode 114 is disposed over the OLED material 112. The cathode 114 includes a conductive material such as a metal or a metal alloy. For example, the cathode 114 includes, but is not limited to, silver, magnesium, aluminum, ITO, or a combination thereof. The material of the cathode 114 is different from the materials of the OLED material 112 and the PDL structure 126. The cathode 114 further includes a first cathode end 114A in contact with the first sidewall 122B of the first heat absorbing structure 121A. The cathode 114 includes a second cathode end 114B in contact with the second sidewall 122C of the second heat absorbing structure 121B. The cathode 114 is disposed over the PDL structure 126.

[0020] Each subpixel 106 includes an encapsulation layer 116. Subpixel circuit 100A includes a first encapsulation layer 116A for first subpixel 108A. Subpixel circuit 100A further includes a second encapsulation layer 116B for second subpixel 108B. The encapsulation layer 116 may be or correspond to a local passivation layer. The encapsulation layer 116 for each subpixel is disposed over cathode 114 (and OLED material 112). The encapsulation layer 116 includes a first encapsulation sidewall 117A and a second encapsulation sidewall 117B. The first encapsulation layer 116A contacts a first portion of the top surface 122A of first heat absorbing structure 121A. The first encapsulation layer 116A also contacts a second portion of the top surface 122A of second heat absorbing structure 121B. The second encapsulation layer 116B contacts a first portion of the top surface 122A of the second heat absorbing structure 121B. In some embodiments, a gap 150 exists between the first encapsulation layer 116A on the second portion of the top surface 122A of the second heat absorbing structure 121B and the second encapsulation layer 116B on the first portion of the top surface 122A of the second heat absorbing structure 121B. In some embodiments, the second encapsulation layer 116B overlaps the first encapsulation layer 116A on the top surface 122A of the second heat absorbing structure 121B.

[0021] The encapsulation layer 116 may have a thickness between 0.1 μm and 2 μm. The encapsulation layer 116 comprises a non-conductive inorganic material, such as a silicon-containing material. The silicon-containing material may comprise a SiN-containing material. The material of the encapsulation layer 116 is different from the materials of the cathode 114, the OLED material 112, and the PDL structure 126. In some embodiments, the subpixel circuit 100A further comprises a global encapsulation layer (not shown) disposed over the encapsulation layer 116 and over the uncovered portion of the heat absorbing structure 121.

[0022] 1B is a schematic cross-sectional view of a subpixel circuit 100B. The cross-sectional view of FIG. 1B is taken along section line 1"-1" of FIG. 1C.

[0023] The subpixel circuit 100B includes a substrate 102. A metal-containing layer 104 may be patterned on the substrate 102, and the metal-containing layer 104 is defined by adjacent heat-absorbing structures 121 disposed on the substrate 102. In one embodiment, the metal-containing 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-containing layer 104 is configured to act as the anode for each subpixel. The metal-containing layer 104 may include, but is not limited to, chromium, titanium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials.

[0024] The heat absorbing structure 121 is disposed on the substrate 102. The heat absorbing structure 121 includes a top surface 122A coupled to a first sidewall 122B and a second sidewall 122C. Both the first sidewall 122B and the second sidewall 122C have tapered edges. The heat absorbing structure 121 includes one of an organic material, an organic material having an inorganic coating disposed thereon, or an inorganic material. The organic material of the heat absorbing structure 121 includes, but is not limited to, polyimide. The inorganic material of the heat absorbing structure 121 includes, but is not limited to, silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiNO), magnesium fluoride (MgF), or a combination thereof. In some embodiments, the heat absorbing structure 121 includes a metal layer. The metal layer includes, but is not limited to, molybdenum or titanium. In some embodiments, the heat absorbing structure 121 includes a multilayer structure. The multilayer structure may include a metal layer, a transparent layer, and another metal layer. The metal layer may include, but is not limited to, molybdenum or titanium. The transparent layer may include, but is not limited to, silicon oxide (SiO2) or silicon nitride (SiN x ) is included.

[0025] Adjacent heat absorbing structures 121 define each subpixel 106 and expose the anode (i.e., metal-containing layer 104) of each subpixel 106 in subpixel circuit 100B. In subpixel circuit 100B, heat absorbing structure 121 functions as the PDL structure 126 of subpixel circuit 100A. Heat absorbing structure 121 absorbs energy and generates heat. The generated heat is localized to heat absorbing structure 121. This localized heating of heat absorbing structure 121 removes material disposed on top surface 122A of heat absorbing structure 121. This material may be OLED material 112 or, in some embodiments, cathode 114. This material may be removed by evaporation.

[0026] The subpixel circuit 100B includes at least a first subpixel 108A and a second subpixel 108B. While the figure shows a first subpixel 108A and a second subpixel 108B, the subpixel circuit 100B of the embodiments described herein may include more than two subpixels 106, such as a third and fourth subpixel. Each subpixel 106 has organic light-emitting diode (OLED) material 112 configured to emit white, red, green, blue, or other color light when energized. For example, the OLED material 112 of the first subpixel 108A emits red light when energized, the OLED material 112 of the second subpixel 108B emits green light when energized, the OLED material 112 of the third subpixel emits blue light when energized, and the OLED material 112 of the fourth and fifth subpixels emit light of another color when energized. The OLED material 112 is different from the material of the heat absorbing structure 121 .

[0027] OLED material 112 is disposed on metal-containing layer 104. OLED material 112 is disposed along a first sidewall 122B of first heat absorbing structure 121A. OLED material 112 contacts top surface 122A of first heat absorbing structure 121A at first OLED edge 112A. OLED material 112 is disposed along a second sidewall 122C of second heat absorbing structure 121B. OLED material 112 contacts top surface 122A of second heat absorbing structure 121B at second OLED edge 112B.

[0028] The cathode 114 is disposed on the OLED material 112. The cathode 114 includes a conductive material such as a metal or a metal alloy. For example, the cathode 114 includes, but is not limited to, silver, magnesium, aluminum, ITO, or a combination thereof. The material of the cathode 114 is different from the materials of the OLED material 112 and the heat absorbing structure 121. The cathode 114 is disposed along the first sidewall 122B of the first heat absorbing structure 121A and contacts the top surface 122A of the first heat absorbing structure 121A at the first cathode end 114A. The cathode 114 is disposed along the second sidewall 122C of the second heat absorbing structure 121B and contacts the top surface 122A of the second heat absorbing structure 121B at the second cathode end 114B.

[0029] Each subpixel 106 includes an encapsulation layer 116. Subpixel circuit 100B includes a first encapsulation layer 116A for first subpixel 108A. Subpixel circuit 100B further includes a second encapsulation layer 116B for second subpixel 108B. The encapsulation layer 116 may be or correspond to a local passivation layer. The encapsulation layer 116 for each subpixel is disposed over the cathode 114 (and OLED material 112). The encapsulation layer 116 includes a first encapsulation sidewall 117A and a second encapsulation sidewall 117B. The first encapsulation layer 116A contacts a first portion of the top surface 122A of the first heat absorbing structure 121A. The first encapsulation layer 116A also contacts a second portion of the top surface 122A of the second heat absorbing structure 121B. The second encapsulation layer 116B contacts a first portion of the top surface 122A of the second heat absorbing structure 121B. In some embodiments, a gap 150 exists between the first encapsulation layer 116A on the second portion of the top surface 122A of the second heat absorbing structure 121B and the second encapsulation layer 116B on the first portion of the top surface 122A of the second heat absorbing structure 121B. The encapsulation layer 116 may have a thickness of 0.1 μm and 2 μm. In some embodiments, the second encapsulation layer 116B overlaps the first encapsulation layer 116A on the top surface 122A of the second heat absorbing structure 121B. In some embodiments, the subpixel circuit 100B further includes a global encapsulation layer (not shown) disposed on the encapsulation layer 116 and on the uncovered portion of the heat absorbing structure 121B.

[0030] FIG. 1C is a schematic cross-sectional view of a subpixel circuit 100A having a line-type architecture 100C. In another embodiment, the subpixel circuit 100A has a dot-type architecture (not shown). The top cross-sectional view of FIG. 1C is taken along section line 1′-1′ in FIGS. 1A and 1B. The line-type architecture 100C includes multiple pixel openings 124A with adjacent PDL structures 126. Each pixel opening 124A defines a subpixel 106 of the line-type architecture.

[0031] Figure 2 is a flow diagram of a method 200 for forming a sub-pixel circuit according to an embodiment. Figures 3A-3E are schematic cross-sectional views of a portion of a substrate during a method 200 for forming a sub-pixel circuit 300 according to an embodiment.

[0032] In operation 201, a first OLED material 112 is disposed. While FIG. 1A illustrates the first OLED material 112 as red, operations 201-206 and FIGS. 3A-3E illustrate the first OLED material 112 as green. The first OLED material 112 is disposed within a first pixel opening 301, within a second pixel opening (not shown), and on top surfaces 122A of a plurality of adjacent heat absorbing structures 121. The first pixel opening 301 and the second pixel opening are defined by adjacent heat absorbing structures of the plurality of adjacent heat absorbing structures 121. The adjacent heat absorbing structures 121 are disposed on a substrate 102, as shown in FIG. 1B. In another embodiment, the heat absorbing structure 121 is disposed on a PDL structure 126, as shown in FIG. 1A. The PDL structure is disposed on a substrate 102, as shown in FIG. 1A. A first OLED material 112 is disposed over the metal-containing layer 104 .

[0033] In operation 202, a cathode 114 is disposed over the first OLED material 112. The cathode 114 is disposed in the first pixel opening 301, in the second pixel opening, and on the top surfaces 122A of a plurality of adjacent heat absorbing structures 121. Figure 3A shows both operation 201 and operation 202.

[0034] In operation 203, the first OLED material 112 and the cathode 114 on the top surfaces 122A of the plurality of adjacent heat absorbing structures 121 are removed. The first OLED material 112 is removed by one or more of flash evaporation, Joule heating, and a laser. The flash evaporation, Joule heating, or laser causes the heat absorbing structures 121 to absorb energy. This energy generates heat. This localized heating of the heat absorbing structures 121 removes the OLED material 112 and the cathode 114 disposed on the top surfaces 122A of the heat absorbing structures 121. The OLED material 112 and the cathode 114 may be removed by evaporation. Removing the OLED material 112 from the top surfaces 122A brings the first OLED terminals 112A into contact with the top surfaces 122A of the first heat absorbing structures 121A. The second OLED terminal 112B contacts the top surface 122A of the second heat absorbing structure 121B. When the cathode 114 is removed from the top surface 122A, the first cathode terminal 114A contacts the top surface 122A of the first heat absorbing structure 121A. The second cathode terminal 114B contacts the top surface 122A of the second heat absorbing structure 121B. Figure 3B shows operation 203.

[0035] In embodiments including the PDL structure 126, removing the OLED material 112 from the top surface 122A brings the first OLED end 112A into contact with the first sidewall 122B of the first heat absorbing structure 121A. The second OLED end 112B comes into contact with the second sidewall 122C of the second heat absorbing structure 121B. Removing the cathode 114 from the top surface 122A brings the first cathode end 114A into contact with the first sidewall 122B of the first heat absorbing structure 121A. The second cathode end 114B comes into contact with the second sidewall 122C of the second heat absorbing structure 121B.

[0036] In operation 204, an encapsulation layer 116 is deposited. The encapsulation layer 116 is deposited on the cathode 114. The encapsulation layer 116 is also deposited on the top surfaces 122A of the plurality of adjacent heat absorbing structures 121. Figure 3C illustrates operation 204.

[0037] In operation 205, photoresist 305 is formed on encapsulation layer 116. Photoresist 305 is formed on encapsulation layer 116 in first pixel opening 301. Photoresist 305 is also formed on a first portion of top surface 122A of first heat absorbing structure 121A. Photoresist 305 is also formed on a second portion of top surface 122A of second heat absorbing structure 121B. Photoresist 305 is a positive resist or a negative resist. A positive resist includes portions of the resist that, when exposed to electromagnetic radiation, become soluble to a resist developer that is applied to the resist after a pattern is written into the resist using electromagnetic radiation. A negative resist includes portions of the resist that, when exposed to electromagnetic radiation, become insoluble to a resist developer that is applied to the resist after a pattern is written into the resist using electromagnetic radiation. The chemical composition of the photoresist 305 determines whether the resist is a positive or negative resist. The patterning is one of photolithography, digital lithography processes, or laser ablation processes. Figure 3D shows operation 205.

[0038] In operation 206, the encapsulation layer exposed by photoresist 305 is removed. The encapsulation layer 116 can be removed by etching. The encapsulation layer 116 may also be removed by a dry etching process. Figure 3E illustrates operation 206.

[0039] Operations 201-206 are repeated for a second OLED material, such as a red OLED material or a blue OLED material. In operation 201, the second OLED material is disposed on the encapsulation layer 116 in the first pixel opening 301 and the second pixel opening and on the top surface 122A of the adjacent heat absorbing structure 121.

[0040] Figure 4 is a flow diagram of a method 400 of forming a sub-pixel circuit according to an embodiment. Figures 5A-5E are schematic cross-sectional views of a portion of a substrate during a method 400 of forming an OLED pixel structure 500 according to an embodiment.

[0041] In operation 401, a first OLED material 112 is disposed. While FIG. 1A illustrates the first OLED material 112 as red, operations 401-406 and FIGS. 5A-5E illustrate the first OLED material 112 as green. The first OLED material 112 is disposed within a first pixel opening 501, within a second pixel opening (not shown), and on top surfaces 122A of a plurality of adjacent heat absorbing structures 121. The first pixel opening 501 and the second pixel opening are defined by adjacent heat absorbing structures of the plurality of adjacent heat absorbing structures 121. The adjacent heat absorbing structures 121 are disposed on the top PDL surface 127A of the PDL structure 126. As shown in FIG. 1A, the PDL structure is disposed on a substrate 102. In some embodiments, as shown in FIG. 1B, adjacent heat absorbing structures 121 are disposed on a substrate 102 without a PDL structure 126. A first OLED material 112 is disposed over the metal-containing layer 104. Figure 5A shows operation 401.

[0042] In operation 402, the first OLED material 112 on the top surfaces 122A of the plurality of adjacent heat absorbing structures 121 is removed. The first OLED material 112 is removed by one or more of flash evaporation, Joule heating, and a laser. Flash evaporation, Joule heating, or a laser causes the heat absorbing structures 121 to absorb energy. This energy generates heat. This localized heating of the heat absorbing structures 121 removes the OLED material 112 from the top surfaces 122A of the heat absorbing structures 121. The OLED material 112 may be removed by evaporation. Upon removing the OLED material 112 from the top surfaces 122A, the first OLED edge 112A contacts the first sidewall 122B of the first heat absorbing structure 121A. The second OLED edge 112B contacts the second sidewall 122C of the second heat absorbing structure 121B. In embodiments without PDL structure 126, removing OLED material 112 from top surface 122A causes first OLED terminal 112A to contact top surface 122A of first heat absorbing structure 121A. Second OLED terminal 112B to contact top surface 122A of second heat absorbing structure 121B. Figure 5B shows operation 402.

[0043] In operation 403, a cathode 114 is disposed. The cathode 114 is disposed within the first pixel opening 301, within the second pixel opening, and on the top surfaces 122A of the plurality of adjacent heat absorbing structures 121.

[0044] In operation 404, an encapsulation layer 116 is deposited on the cathode 114. The encapsulation layer 116 is deposited in the first pixel opening 501 and the second pixel opening. The encapsulation layer 116 is also deposited on the top surfaces 122A of the plurality of adjacent heat absorbing structures 121. Figure 5C shows operation 403 and operation 404.

[0045] In operation 405, photoresist 505 is formed on encapsulation layer 116. Photoresist 505 is formed on encapsulation layer 116 in first pixel opening 501. Photoresist 505 is also formed on a first portion of top surface 122A of first heat absorbing structure 121A. Photoresist 505 is also formed on a second portion of top surface 122A of second heat absorbing structure 121B. Photoresist 505 is a positive resist or a negative resist. A positive resist includes portions of the resist that, when exposed to electromagnetic radiation, become soluble to a resist developer that is applied to the resist after a pattern is written into the resist using electromagnetic radiation. A negative resist includes portions of the resist that, when exposed to electromagnetic radiation, become insoluble to a resist developer that is applied to the resist after a pattern is written into the resist using electromagnetic radiation. The chemical composition of the photoresist 505 determines whether the resist is a positive or negative resist. The photoresist 505 is patterned to form one of the pixel openings of the line-type architecture 100C of the first subpixel 108A. This patterning is one of photolithography, digital lithography, or laser ablation processes. Figure 5D shows operation 405.

[0046] In operation 406, the encapsulation layer 116 and the cathode 114 exposed by the photoresist are removed. The encapsulation layer 116 and the cathode 114 can be removed by etching. The encapsulation layer 116 and the cathode 114 may also be removed by a dry etching process. Upon removing the cathode 114, the first cathode end 114A extends over a first portion of the top surface 122A of the first heat absorbing structure 121A. The second cathode end 114B extends over a second portion of the top surface 122A of the second heat absorbing structure 121B. FIG. 5E illustrates operation 406.

[0047] Operations 401-406 are repeated for a second OLED material, such as a red OLED material or a blue OLED material. In operation 401, the second OLED material is disposed on the encapsulation layer 116 in the first pixel opening 501 and the second pixel opening and on the top surface 122A of the adjacent heat absorbing structure 121.

[0048] In summary, the embodiments described herein relate generally to displays. More particularly, the embodiments described herein relate to subpixel circuits that may be utilized in displays such as OLED displays.

[0049] 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 appended claims.

Claims

1. A device, A substrate; a plurality of heat absorbing structures disposed on the substrate, each heat absorbing structure comprising: The top surface and Two side walls and a plurality of heat absorbing structures having a plurality of sub-pixels defined by the heat absorbing structure, each sub-pixel comprising: an anode; an organic light emitting diode (OLED) material disposed on the anode; extending along a first sidewall of a first heat absorbing structure and contacting the top surface of the first heat absorbing structure at a first OLED edge; extending along a second sidewall of a second heat absorbing structure and contacting the top surface of the second heat absorbing structure at a second OLED edge; an OLED material; a cathode disposed over the OLED material; extending along the first sidewall of the first heat absorbing structure and contacting the top surface of the first heat absorbing structure at a first cathode end; extending along the second sidewall of the second heat absorbing structure and contacting the top surface of the second heat absorbing structure at a second cathode end; a cathode; an encapsulation layer disposed over the cathode, the encapsulation layer contacting a first portion of the top surface of the first heat absorbing structure and a second portion of the top surface of the second heat absorbing structure; a plurality of sub-pixels, A device comprising:

2. The device of claim 1 , wherein the two sidewalls of the plurality of heat absorbing structures have tapered edges.

3. 2. The device of claim 1 , wherein the encapsulation layer of a first subpixel on the second portion of the top surface of the second heat absorbing structure and the encapsulation layer of a second subpixel on the first portion of the top surface of the second heat absorbing structure have a gap therebetween.

4. 10. The device of claim 1, wherein the encapsulation layer of a second subpixel overlaps the encapsulation layer of a first subpixel on the top surface of the second heat absorbing structure.

5. 10. The device of claim 1, wherein the cathode contacts the first portion of the top surface of the first heat absorbing structure and the second portion of the top surface of the second heat absorbing structure.

6. A device, A substrate; a plurality of pixel definition layer (PDL) structures disposed over the substrate, each PDL structure having a top PDL surface; a plurality of heat absorbing structures disposed on the upper PDL surface of the plurality of PDL structures, each adjacent heat absorbing structure comprising: The top surface and Two side walls and a plurality of heat absorbing structures comprising: Equipped with Adjacent heat absorbing structures define subpixels of the device, each subpixel comprising: an anode; an organic light emitting diode (OLED) material disposed over the anode, the OLED material having a first OLED end in contact with a first sidewall of the first heat absorbing structure and a second OLED end in contact with a second sidewall of the second heat absorbing structure; a cathode disposed over the OLED material, the cathode having a first cathode end in contact with the first sidewall of the first heat absorbing structure and a second cathode end in contact with the second sidewall of the second heat absorbing structure; an encapsulation layer disposed over the cathode and over a first portion of the top surface of the first heat absorbing structure and a second portion of the top surface of the second heat absorbing structure; A device comprising:

7. The device of claim 6 , wherein the encapsulation layer contacted the first portion of the top surface of the first heat absorbing structure and the second portion of the top surface of the second heat absorbing structure.

8. The device of claim 6 , wherein the cathode contacts the first portion of the top surface of the first heat absorbing structure and the second portion of the top surface of the second heat absorbing structure.

9. The device of claim 6 , wherein the two sidewalls of the plurality of heat absorbing structures have reverse tapered edges.

10. 7. The device of claim 6, wherein the encapsulation layer of a first subpixel over the second portion of the second heat absorbing structure and the encapsulation layer of a second subpixel over the first portion of the second heat absorbing structure have a gap therebetween.

11. 7. The device of claim 6, wherein the encapsulation layer of a second subpixel overlaps the encapsulation layer of a first subpixel on the top surface of the second heat absorbing structure.

12. 1. A method comprising: disposing a first OLED material in a first pixel opening over the anode, in a second pixel opening, and on top surfaces of a plurality of adjacent heat absorbing structures disposed on a substrate, the first pixel opening and the second pixel opening being defined by adjacent heat absorbing structures of the plurality of adjacent heat absorbing structures; disposing a cathode over the first OLED material; removing the first OLED material and the cathode on the top surfaces of the plurality of adjacent heat absorbing structures; depositing an encapsulation layer over the cathode and over the top surfaces of the plurality of adjacent heat absorbing structures; forming a photoresist over the encapsulation layer in the first pixel opening and over a first portion of the top surface of the first heat absorbing structure and a second portion of the top surface of the second heat absorbing structure; removing the encapsulation layer exposed by the photoresist; A method comprising:

13. 13. The method of claim 12, wherein the OLED material has a first OLED end in contact with a top surface of the first heat absorbing structure and a second OLED end in contact with a top surface of the second heat absorbing structure.

14. 13. The method of claim 12, wherein the cathode has a first cathode end in contact with a top surface of the first heat absorbing structure and a second cathode end in contact with a top surface of the second heat absorbing structure.

15. 13. The method of claim 12, wherein the heat absorbing structure absorbs energy to generate heat, the heat removing the first OLED material and the cathode on the top surface of the heat absorbing structure.

16. 16. The method of claim 15, wherein the heat absorbing structure absorbs energy from a flash evaporation process, and the first OLED material and the cathode are removed by evaporation.

17. 1. A method comprising: disposing a first OLED material in a first pixel opening over the anode, in a second pixel opening, and on top surfaces of a plurality of adjacent heat absorbing structures disposed on a substrate, the first pixel opening and the second pixel opening being defined by adjacent heat absorbing structures of the plurality of adjacent heat absorbing structures; removing the first OLED material on the top surfaces of the plurality of adjacent heat absorbing structures; disposing a cathode over the first OLED material and over the top surfaces of the plurality of adjacent heat absorbing structures; depositing an encapsulation layer over the cathode; forming a photoresist over the encapsulation layer in the first pixel opening and over a first portion of the top surface of the first heat absorbing structure and a second portion of the top surface of the second heat absorbing structure; removing the encapsulation layer and the cathode on the first portion of the top surface of the first heat absorbing structure and the second portion of the top surface of the second heat absorbing structure exposed by the photoresist; A method comprising:

18. 20. The method of claim 17, wherein the OLED material has a first OLED end in contact with a top surface of the first heat absorbing structure and a second OLED end in contact with a top surface of the second heat absorbing structure.

19. 18. The method of claim 17, wherein the cathode has a first cathode end point on the first portion of the top surface of the first heat absorbing structure and a second cathode end point on the second portion of the top surface of the second heat absorbing structure.

20. 20. The method of claim 17, wherein the heat absorbing structure absorbs energy to generate heat, the heat removing the first OLED material on the top surface of the heat absorbing structure.

Images