Multiple suspension for enhanced pixel packaging

Abstract

Embodiments described herein relate to an apparatus including a substrate, a plurality of suspension structures, and a plurality of sub-pixels. The plurality of suspension structures includes a first structure, a second structure disposed over an upper surface of the first structure, an adjacent first suspension, a third structure disposed over the second structure, and an adjacent second suspension. Each first suspension is defined by a first suspension extension of the second structure extending laterally beyond an upper surface of the first structure. Each sub-pixel includes an anode, an organic light emitting diode (OLED) material disposed over the anode, and a cathode disposed over the OLED material.

Description

Technical Field

[0001] Embodiments described herein generally relate to displays. More specifically, embodiments described herein relate to sub-pixel circuits that can be used in displays such as organic light emitting diode (OLED) displays and methods of forming the sub-pixel circuits. Background Art

[0002] Input devices including display devices can be used in various electronic systems. An organic light emitting diode (OLED) is a light emitting diode (LED) in which the emitting electroluminescent layer is a film of organic compounds that emits light in response to an electric current. An OLED device is classified as a bottom emitting device if the emitted light passes through a transparent or translucent bottom electrode and substrate on which the panel is manufactured. Top emitting devices are classified based on whether the light emitted from the OLED device leaves through a cover that is added after the device is manufactured. OLEDs are used to create display devices in many of today's electronic products. Today's electronic product manufacturers are pushing these display devices to be smaller in size while providing higher resolution than was possible a few years ago.

[0003] OLED pixel patterning is currently based on processes that limit panel size, pixel resolution, and substrate size. Instead of using fine metal masks, photolithography should be used to pattern the pixels. Currently, OLED pixel patterning requires stripping of the organic material after the patterning process. When stripped, the organic material leaves behind particle problems that damage OLED performance. Thus, what is needed in the art is a sub-pixel circuit and a method of forming a sub-pixel circuit to increase pixels per inch and provide improved OLED performance. Summary of the invention

[0004] In one embodiment, a device is provided. The device includes a substrate, a plurality of suspension structures, and a plurality of sub-pixels. The plurality of suspension structures include a first structure, a second structure disposed above an upper surface of the first structure, an adjacent first suspension, a third structure disposed above the second structure, and an adjacent second suspension. Each first suspension is defined by a first suspension extension of the second structure extending laterally beyond an upper surface of the first structure. Each sub-pixel includes an anode, an organic light emitting diode (OLED) material disposed above the anode, and a cathode disposed above the OLED material.

[0005] In another embodiment, a device is provided. The device includes a substrate, a plurality of suspension structures disposed above the substrate, and a plurality of sub-pixels. Each suspension structure includes a first structure, a second structure disposed above the upper surface of the first structure, an adjacent first suspension, and an adjacent second suspension. The second structure includes an inner plane, an upper surface, an upper side wall formed between the inner plane and the upper surface, a bottom surface, and a lower side wall formed between the inner plane and the bottom surface. Each first suspension is defined by a first suspension extension portion of the second structure that extends laterally beyond the upper surface of the first structure. Each second suspension is formed by an upper side wall. Each sub-pixel includes an anode, an organic light emitting diode (OLED) material disposed above the anode, and a cathode disposed above the OLED material.

[0006] In another embodiment, a method is provided. The method includes depositing a first structure layer and a second structure layer over a substrate. Removing a portion of the second structure layer exposed by the resist to form a second structure and a third structure. Removing a portion of the first structure layer exposed by the resist to form the first structure. Removing the resist from the third structure. Depositing an organic light emitting diode (OLED) material, a cathode, and an encapsulation layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Therefore, in order to be able to understand in detail the manner in which the above-mentioned features of the present disclosure are used, a more specific description of the present disclosure briefly summarized above can be made with reference to various embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings only illustrate exemplary embodiments and are not to be considered as limiting the scope thereof, and other equivalent embodiments may be allowed.

[0008] Figure 1A is a schematic cross-sectional view of a sub-pixel circuit according to an embodiment.

[0009] Figure 1B is a schematic cross-sectional view of a suspension structure of a sub-pixel circuit according to an embodiment.

[0010] Figure 1C is a schematic cross-sectional view of a sub-pixel circuit according to an embodiment.

[0011] Figure 1D is a schematic cross-sectional view of a suspension structure of a sub-pixel circuit according to an embodiment.

[0012] Figure 2 is a schematic cross-sectional view of a suspension structure of a sub-pixel circuit according to an embodiment.

[0013] Figure 3 is a schematic cross-sectional view of a suspension structure of a sub-pixel circuit according to an embodiment.

[0014] Figure 4is a schematic cross-sectional view of a suspension structure of a sub-pixel circuit according to an embodiment.

[0015] Figure 5 is a schematic cross-sectional view of a suspension structure of a sub-pixel circuit according to an embodiment.

[0016] Figure 6 is a schematic cross-sectional view of a suspension structure of a sub-pixel circuit according to an embodiment.

[0017] Figure 7 is a flow chart of a method 700 for forming a sub-pixel circuit.

[0018] FIG. 8A to FIG. 8D is a schematic cross-sectional view of a substrate during a method for forming a sub-pixel circuit.

[0019] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. DETAILED DESCRIPTION

[0020] Embodiments described herein generally relate to a display. More specifically, embodiments described herein relate to subpixel circuits that can be used in displays such as organic light emitting diode (OLED) displays and methods of forming the subpixel circuits. In various embodiments, subpixels employ advanced suspension structures to improve the functionality of the display.

[0021] Each embodiment of the sub-pixel circuit described herein includes a plurality of sub-pixels, wherein each sub-pixel is defined by an adjacent suspension structure that is permanent to the sub-pixel circuit. Although the accompanying drawings depict two sub-pixels, wherein each sub-pixel is defined by an adjacent suspension structure, the sub-pixel circuit of the embodiment described herein includes a plurality of sub-pixels, such as two or more sub-pixels. Each sub-pixel has an OLED material configured to emit white, red, green, blue or other color light when powered on. For example, the OLED material of the first sub-pixel emits red light when powered on, the OLED material of the second sub-pixel emits green light when powered on, and the OLED material of the third sub-pixel emits blue light when powered on.

[0022] The suspension is permanent to the sub-pixel circuit and includes at least a second structure disposed above the first structure. The adjacent suspension structures of each sub-pixel defining the sub-pixel circuit of the display are used to form the sub-pixel circuit using evaporative deposition, and are used to keep the suspension structure in place after the sub-pixel circuit is formed. Evaporative deposition is used to deposit OLED materials (including a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), and an electron transport layer (ETL)) and a cathode. In some cases, an encapsulation layer may be disposed via evaporative deposition. In an embodiment including one or more covering layers, the covering layer is disposed between the cathode and the encapsulation layer. The encapsulation layer of the corresponding sub-pixel is disposed above the cathode.

[0023] Figure 1A is a schematic cross-sectional view of the first sub-pixel circuit 100A. Figure 1B 1 is a schematic cross-sectional view of a suspension structure 110 of a first sub-pixel circuit 100A. The first sub-pixel circuit 100A includes a substrate 102. A metal-containing layer 104 may be patterned on the substrate 102 and defined by an adjacent pixel structure (PS) 126A disposed on the substrate 102. In one embodiment, the PS 126A is 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 pre-patterned with a metal-containing layer 104 of indium tin oxide (ITO). The metal-containing layer 104 is configured to operate as an anode of a corresponding sub-pixel. In one embodiment, the metal-containing layer 104 is a first transparent conductive oxide (TCO) layer, a second metal-containing layer disposed on the first TCO layer, and a layer stack of a third TCO layer disposed on the second metal-containing layer. The metal-containing layer 104 includes, but is not limited to, chromium, titanium, gold, silver, copper, aluminum, ITO, a combination thereof, or other suitable conductive materials.

[0024] A plurality of PS126A are disposed above the substrate 102. The PS126A includes an organic material, an organic material having an inorganic coating disposed thereon, or one of an inorganic material. The organic material of the PS126A includes, but is not limited to, polyimide. The inorganic material of the PS126A includes, but is not limited to, silicon oxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (Si2N2O), magnesium fluoride (MgF2), or a combination thereof. Adjacent PS126A define corresponding sub-pixels and expose the anode (i.e., metal-containing layer 104) of the corresponding sub-pixel circuit 100.

[0025] The first sub-pixel circuit 100A has a plurality of sub-pixels 106 including at least a first sub-pixel 108A and a second sub-pixel 108B. Although the drawings depict the first sub-pixel 108A and the second sub-pixel 108B, the first sub-pixel circuit 100A of the 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 configured to emit white, red, green, blue, or other color light when powered on. For example, the OLED material of the first sub-pixel 108A emits red light when powered on, the OLED material of the second sub-pixel 108B emits green light when powered on, the OLED material of the third sub-pixel emits blue light when powered on, and the OLED material of the fourth sub-pixel emits another color of light when powered on.

[0026] Each sub-pixel 106 includes a suspension structure 110. The suspension structure 110 is permanent to the first sub-pixel circuit 100A. The suspension structure 110 further defines each sub-pixel 106 of the first sub-pixel circuit 100A. Each suspension structure 110 includes an adjacent first suspension 117 and an adjacent second suspension 109. The adjacent first suspension is formed by a first suspension extension 117A (such as a first suspension extension portion 117A) of the second structure 110B extending laterally beyond the upper surface 105 of the first structure 110A. Figure 1B The first structure 110A is defined on the upper surface 103 (as shown in FIG. Figure 1B The adjacent second suspension 109 is formed by a second suspension extension portion 109A (as shown) extending laterally from the third structure 110C beyond the upper surface 115 of the second structure 110B. Figure 1B The third structure 110C is disposed above the second structure 110B.

[0027] In one embodiment, the second structure 110B and the third structure 110C include non-conductive inorganic materials, and the first structure 110A includes conductive inorganic materials. The conductive material of the first structure 110A includes aluminum (Al), aluminum neodymium (AlNd), molybdenum (Mo), molybdenum tungsten (MoW), copper (Cu), or a combination thereof. The inorganic materials of the second structure 110B and the third structure 110C include titanium (Ti), silicon nitride (Si3N4), silicon oxide (SiO2), silicon oxynitride (Si2N2O), or a combination thereof. The suspension structure 110 can be maintained in place, i.e., it is permanent. In one embodiment, the first structure 110A includes a metal-containing material. In one example, the metal-containing material is a transparent conductive oxide (TCO) material. TCO materials include, but are not limited to, indium zinc oxide (IZO), indium tin oxide (ITO), indium gallium zinc oxide (IGZO), or a combination thereof. In another embodiment, the first structure 110A, the second structure 110B, and the third structure 110C include conductive materials.

[0028] The adjacent first suspension 117 is defined by a first suspension extension 117A. At least the bottom surface 107 of the second structure 110B is wider than the upper surface 105 of the first structure 110A to form the first suspension extension 117A. The first suspension extension 117A of the second structure 110B forms the first suspension 117 and allows the second structure 110B to shield the first structure 110A. The shielding of the first suspension 117 is used for the evaporation deposition of the OLED material 112 and the cathode 114. The OLED material 112 may include one or more of the HIL, HTL, EML, and ETL. The OLED material is disposed above and in contact with the metal-containing layer 104. The OLED material 112 is disposed below the adjacent first suspension 117. The cathode 114 includes a conductive material, such as a metal. For example, the cathode 114 includes, but is not limited to, silver, magnesium, chromium, titanium, aluminum, ITO, or a combination thereof. The cathode 114 is disposed above the sidewalls of the OLED material 112 and the second structure 110B of the suspension structure 110.

[0029] The adjacent second overhang 109 is defined by the second overhang extension 109A of the third structure 110C. At least the bottom surface 121 of the third structure 110C is wider than the upper surface 115 of the second structure 110B to form the second overhang extension 109A of the second overhang 109. The third structure 110C is disposed above the upper surface 115 of the second structure 110B. The second overhang extension 109A of the third structure 110C forms the second overhang 109 and allows the third structure 110C to shield the second structure 110B. The shielding of the second overhang 109 is used for evaporation deposition of each of the OLED material 112 and the cathode 114. Each of the OLED material 112 and the cathode 114 is disposed below the second overhang 109.

[0030] Cathode 114 includes a conductive material, such as a metal. For example, cathode 114 includes, but is not limited to, silver, magnesium, chromium, titanium, aluminum, ITO, or a combination thereof. In one embodiment, the material of cathode 114 is different from the material of first structure 110A, second structure 110B, and third structure 110C. In some embodiments, OLED material 112 and cathode 114 are disposed on sidewall 111 of first structure 110A. OLED material 112 and cathode 114 are not disposed over sidewall 123 of second structure 110B or sidewall 124 of third structure 110C.

[0031] Each sub-pixel 106 includes an encapsulation layer 116. The encapsulation layer 116 may be or may correspond to a local passivation layer. The encapsulation layer 116 of the corresponding sub-pixel is disposed above the cathode 114 (and the OLED material 112), wherein the encapsulation layer 116 extends under at least a portion of each of the first suspension 117 and the second suspension 109. 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.

[0032] In an embodiment including one or more covering layers, the covering layer is disposed between the cathode 114 and the encapsulation layer 116. For example, a first covering layer and a second covering layer are disposed between the cathode 114 and the encapsulation layer 116. Each of the embodiments described herein may include one or more covering layers disposed between the cathode 114 and the encapsulation layer 116. The first covering layer may include an organic material. The second covering layer may include an inorganic material, such as lithium fluoride. The first covering layer and the second covering layer may be deposited by evaporative deposition. In another embodiment, the first sub-pixel circuit 100A further includes at least a global passivation layer 120 disposed above the suspension structure 110 and the encapsulation layer 116. In yet another embodiment, the sub-pixel includes an intermediate passivation layer disposed above the suspension structure 110 of each sub-pixel 106 and disposed between the encapsulation layer 116 and the global passivation layer 120.

[0033] The encapsulation layer 116 is disposed within the adjacent second suspension 109. Therefore, the adjacent second suspension 109 is used to reduce moisture intrusion into the suspension structure 110. Due to the contact between the encapsulation layer 116 and the second structure 110B, the adjacent second suspension 109 establishes a more complex moisture intrusion path. When moisture intrudes into the suspension structure 110, the encapsulation layer 116 within the adjacent second suspension 109 establishes a barrier between the moisture and the second structure 110B, thereby preventing moisture from intruding into the adjacent first suspension 117.

[0034] Figure 1C is a schematic cross-sectional view of a second sub-pixel circuit 100B according to the embodiment. Figure 1D1 is a schematic cross-sectional view of a second sub-pixel circuit 100B according to an embodiment. The second sub-pixel circuit 100B includes a substrate 102. A base layer 125 may be patterned above the substrate 102. The base layer 125 includes, but is not limited to, a CMOS layer. A metal-containing layer 104 (e.g., an anode) may be patterned on the base layer 125 and defined by an adjacent pixel structure (PS) 126B disposed on the substrate 102. In one embodiment, the metal-containing layer 104 is pre-patterned on the base layer 125. For example, the base layer 125 is pre-patterned with a metal-containing layer 104 of indium tin oxide (ITO). The metal-containing layer 104 may be disposed on the substrate 102. The metal-containing layer 104 is configured to operate as an anode of a corresponding sub-pixel. In one embodiment, the metal-containing layer 104 is a layer stack of a first transparent conductive oxide (TCO) layer, a second metal-containing layer disposed on the first TCO layer, and a third TCO layer disposed on the second metal-containing layer. The metal-containing layer 104 includes, but is not limited to, chromium, titanium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials.

[0035] PS126B is arranged above substrate 102. PS126B can be arranged on base layer 125. PS126B includes one of organic material, organic material with inorganic coating arranged above it, or inorganic material. The organic material of PS126B includes but is not limited to polyimide. The inorganic material of PS126B includes but is not limited to silicon oxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (Si2N2O), magnesium fluoride (MgF2), or a combination thereof. Adjacent PS126B defines corresponding sub-pixels and exposes the metal-containing layer 104 of the corresponding second sub-pixel circuit 100B.

[0036] The second sub-pixel circuit 100B has a plurality of sub-pixel lines (e.g., a first sub-pixel line 106A and a second sub-pixel line 106B). The sub-pixel lines are adjacent to each other along the pixel plane. Each sub-pixel line includes at least two sub-pixels. For example, the first sub-pixel line 106A includes a first sub-pixel 108A and a second sub-pixel (not shown), and the second sub-pixel line 106B includes a third sub-pixel 108C and a fourth sub-pixel (not shown). Although Figure 1ADepicted are the first sub-pixel line 106A and the second sub-pixel line 106B, but the second sub-pixel circuit 100B of the embodiment described herein may include two or more sub-pixel lines, such as the third sub-pixel line and the fourth sub-pixel. Each sub-pixel line has an OLED material configured to emit white, red, green, blue or other colors of light when powered on. For example, the OLED material of the first sub-pixel line 106A emits red light when powered on, the OLED material of the second sub-pixel line 106B emits green light when powered on, the OLED material of the third sub-pixel line emits blue light when powered on, and the OLED material of the fourth sub-pixel emits another color of light when powered on. The OLED material in the pixel line can be configured to emit light of the same color when powered on. For example, the OLED material of the first sub-pixel 108A and the second sub-pixel of the first sub-pixel line 106A emits red light when powered on, and the OLED material of the third sub-pixel 108C and the fourth sub-pixel of the second sub-pixel line 106B emits green light when powered on.

[0037] Each sub-pixel line includes adjacent suspension structures 110, wherein adjacent sub-pixel lines share adjacent suspension structures 110. The suspension structures 110 are permanent for the second sub-pixel circuit 100B. The suspension structures 110 further define each sub-pixel line of the second sub-pixel circuit 100B. Each suspension structure 110 includes adjacent suspensions 117 and 109. The adjacent suspensions 117 and 109 are defined by a first suspension extension 117A of the second structure 110B that extends laterally beyond the upper surface 105 of the first structure 110A and a second suspension extension 109A of the third structure 110C that extends laterally beyond the upper surface 115 of the second structure 110B. The first structure 110A is disposed above the upper surface 103 of the PS 126B. The first endpoint 120A of the bottom surface 118 of the first structure 110A can extend to or beyond the first edge 127A of the PS 126B. The second end point 120B of the bottom surface of the first structure 110A may extend to or beyond a second edge 127B of the PS 126B.

[0038] The second structure 110B is arranged above the first structure 110A. The second structure 110B can be arranged on the upper surface 105 of the first structure 110A. The second structure 110B can also be arranged above the intermediate structure. The intermediate structure can be arranged above the upper surface 105 of the first structure 110A. The intermediate structure can be a seed layer or an adhesive layer. The seed layer serves as a current path for the second sub-pixel circuit 100B. The seed layer may include a titanium (Ti) material. The adhesion promoting layer improves the adhesion between the first structure 110A and the second structure 110B. The adhesive layer may include a chromium (Cr) material. The third structure 110C is arranged above the second structure 110B. The third structure 110C is arranged above the upper surface 115 of the second structure 110B.

[0039] In one embodiment, the second structure 110B and the third structure 110C include a conductive inorganic material, and the first structure 110A is a non-conductive inorganic material. The conductive materials of the second structure 110B and the third structure 110C include copper (Cu), chromium (Cr), aluminum (Al), aluminum neodymium (AlNd), molybdenum (Mo), molybdenum tungsten (MoW), or a combination thereof. The non-conductive material of the first structure 110A includes amorphous silicon (a-Si), titanium (Ti), silicon nitride (Si3N4), silicon oxide (SiO2), silicon oxynitride (Si2N2O), or a combination thereof. The suspension structure 110 is capable of being maintained in place, i.e., permanent.

[0040] The adjacent first suspension 117 is defined by a first suspension extension 117A. At least the bottom surface 107 of the second structure 110B is wider than the upper surface 105 of the first structure 110A to form the first suspension extension 117A. The first suspension extension 117A of the second structure 110B forms the first suspension 117 and allows the second structure 110B to shield the first structure 110A. The shielding of the first suspension 117 is used for the evaporation deposition of the OLED material 112 and the cathode 114. The OLED material 112 may include one or more of the HIL, HTL, EML, and ETL. The OLED material is disposed above and in contact with the metal-containing layer 104. The OLED material 112 is disposed below the adjacent first suspension 117. The cathode 114 includes a conductive material, such as a metal. For example, the cathode 114 includes, but is not limited to, silver, magnesium, chromium, titanium, aluminum, ITO, or a combination thereof. The cathode 114 is disposed over the OLED material 112 and the sidewalls 123 of the second structure 110B and the sidewalls 124 of the third structure 110C of the suspended structure 110 .

[0041] The adjacent second suspension 109 is defined by the second suspension extension 109A of the third structure 110C. At least the bottom surface 121 of the third structure 110C is wider than the upper surface 115 of the second structure 110B to form the second suspension extension 109A of the second suspension 109. The third structure 110C is arranged above the upper surface 115 of the second structure 110B. The second suspension extension 109A of the third structure 110C forms the second suspension 109 and allows the third structure 110C to shield the second structure 110B. The shielding of the second suspension 109 is used for the evaporation deposition of each of the OLED material 112 and the cathode 114. Each of the OLED material 112 and the cathode 114 is arranged below the second suspension 109. The cathode 114 includes a conductive material, such as a metal. For example, the cathode 114 includes but is not limited to silver, magnesium, chromium, titanium, aluminum, ITO, or a combination thereof. In one embodiment, the material of the cathode 114 is different from the material of the first structure 110A, the second structure 110B, and the intermediate structure. In some embodiments, for example, as applied to the second sub-pixel circuit 100B Figure 1C 1, the OLED material 112 and the cathode 114 are disposed over the sidewalls 123 of the second structure 110B of the suspended structure 110 in the pixel plane. In other embodiments, the OLED material 112 and the cathode 114 are disposed over the upper surface 115 of the second structure 110B of the suspended structure 110 in the pixel plane. In still other embodiments, the OLED material 112 and the cathode 114 end on the sidewalls 111 of the first structure 110A, i.e., are not disposed over the sidewalls 123 of the second structure 110B, the sidewalls 124 of the third structure 110C, or the upper surface 122 of the third structure 110C in the pixel plane.

[0042] Each sub-pixel 106 includes an encapsulation layer 116. The encapsulation layer 116 may be or may correspond to a local passivation layer. The encapsulation layer 116 of the corresponding sub-pixel is disposed above the cathode 114 (and the OLED material 112), wherein the encapsulation layer 116 is below at least a portion of each overhang 109 and extends along the sidewall 111 of each of the first structure 110A and the second structure 110B. The encapsulation layer 116 is disposed above the cathode 114 and extends at least to contact the cathode 114 above the sidewall 111 of the first structure 110A in the pixel plane. In some embodiments, the encapsulation layer 116 extends to contact the sidewall 111 of the first structure 110A. In the example Figure 1C and Figure 1DIn the illustrated embodiment shown, encapsulation layer 116 extends to contact second structure 110B at the lower surface and sidewall 123 of first overhang extension 117A, and contacts third structure 110C at the lower surface, sidewall 124 of second overhang extension 109A, and upper surface 122 of third structure 110C. In some embodiments, encapsulation layer 116 extends to contact third structure 110C at the lower surface, sidewall 124, and upper surface 122 of second overhang extension 109A, and when OLED material 112 and cathode 114 are present, encapsulation layer 116 is disposed over OLED material 112 and cathode 114. In some embodiments, encapsulation layer 116 ends at sidewall 111 of first structure 110A, i.e., is not disposed above sidewall 123 of second structure 110B, sidewall 124 of third structure 110C, upper surface 122 of third structure 110C, lower side surface of first overhang extension 117A, or lower side surface of second overhang extension 109A. 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.

[0043] Each subpixel line may be adjacent to a separation structure, wherein adjacent subpixels share adjacent separation structures in a line plane. The separation structure is permanent for the second subpixel circuit 100B. The separation structure further defines each subpixel of the subpixel line of the second subpixel circuit 100B. The separation structure is disposed above the upper surface 103 of the PS126B.

[0044] OLED material 112 is disposed above and in contact with metal-containing layer 104 and separation structure in the plane of the line. Cathode 114 is disposed above OLED material 112 in the plane of the line. Encapsulation layer 116 is disposed above cathode 114 in the plane of the line. Figure 1D As shown, the OLED material 112 , cathode 114 , and encapsulation layer 116 remain continuous along the length of the line plane so that current can be applied across each sub-pixel 106 .

[0045] In an embodiment including one or more covering layers, the covering layer is disposed between the cathode 114 and the encapsulation layer 116. For example, a first covering layer and a second covering layer are disposed between the cathode 114 and the encapsulation layer 116. Each of the embodiments described herein may include one or more covering layers disposed between the cathode 114 and the encapsulation layer 116. The first covering layer may include an organic material. The second covering layer may include an inorganic material, such as lithium fluoride. The first covering layer and the second covering layer may be deposited by evaporative deposition. In another embodiment, the second sub-pixel circuit 100B further includes at least a global passivation layer disposed above the suspension structure 110 and the encapsulation layer 116. In yet another embodiment, the sub-pixel includes an intermediate passivation layer disposed above the suspension structure 110 of each sub-pixel 106 and disposed between the encapsulation layer 116 and the global passivation layer.

[0046] Figure 2 is a schematic cross-sectional view of a suspended structure 210 according to an embodiment. The suspended structure 210 is illustrated without an accompanying substrate 102, metal-containing layer 104, PS 126A / 126B, OLED material 112, cathode 114, or encapsulation layer 116. The suspended structure 210 may be disposed over PS 126A or PS 126B in place of the suspended structure 110.

[0047] Each suspension structure 210 includes an adjacent first suspension 217, an adjacent second suspension 209, and an adjacent third suspension 222. The adjacent first suspension 217 is defined by a first suspension extension 217A of the second structure 210B that extends laterally beyond the upper surface of the first structure 210A. The first structure 210A is disposed above the upper surface 103 of a plurality of adjacent PS126A or PS126B. The adjacent second suspension 209 is defined by a second suspension extension 209A of the third structure 210C that extends laterally beyond the upper surface of the second structure 210B. The third structure 210C is disposed above the second structure 210B.

[0048] The adjacent third suspension 222 is defined by the third extension 222A of the fourth structure 210D. In one embodiment, the fourth structure 210D includes a non-conductive inorganic material. In another embodiment, the fourth structure 210D includes a conductive material. At least the bottom surface of the fourth structure 210D is wider than the upper surface of the third structure 210C to form the third extension 222A of the third suspension 222. The fourth structure 210D is arranged above the upper surface of the third structure 210C. The third extension 222A of the fourth structure 210D forms the third suspension 222 and allows the fourth structure 210D to shield the third structure 210C. The shielding of the third suspension 222 is used for the evaporation deposition of each of the OLED material 112 and the cathode 114. Each of the OLED material 112 and the cathode 114 can be arranged below the third suspension 222.

[0049] Figure 3 is a schematic cross-sectional view of a suspended structure 310 according to an embodiment. The suspended structure 310 is illustrated without an accompanying substrate 102, metal-containing layer 104, PS 126A / 126B, OLED material 112, cathode 114, or encapsulation layer 116. The suspended structure 310 may be disposed over PS 126A or PS 126B in place of the suspended structure 110.

[0050] Each suspension structure 310 includes an adjacent first suspension 317 and an adjacent second suspension 309. The adjacent first suspension 317 is defined by a first suspension extension 317A of the second structure 310B that extends laterally beyond the upper surface of the first structure 310A. The first structure 310A is disposed above the upper surface 103 of a plurality of adjacent PS126A / 126B. The intermediate structure 323 is disposed above the upper surface of the second structure 310B. In one embodiment, the intermediate structure 323 includes a non-conductive inorganic material. In another embodiment, the intermediate structure 323 includes a conductive material. The adjacent second suspension 309 is defined by a second suspension extension 309A of the third structure 310C that extends laterally beyond the upper surface of the second structure 310B.

[0051] The adjacent second overhang 309 is defined by the second overhang extension 309A of the third structure 310C. At least the bottom surface of the third structure 310C is wider than the upper surface of the second structure 310B, the upper surface of the intermediate structure 323, and the bottom surface of the intermediate structure 323 to form the second overhang extension 309A of the second overhang 309. The third structure 310C is disposed above the upper surface of the intermediate structure 323. The second overhang extension 309A of the third structure 310C forms the second overhang 309 and allows the third structure 310C to shield the second structure 310B and the intermediate structure 323.

[0052] Figure 4 4 is a schematic cross-sectional view of a suspended structure 410 according to an embodiment. The suspended structure 410 is illustrated without an accompanying substrate 102, metal-containing layer 104, PS 126A / 126B, OLED material 112, cathode 114, or encapsulation layer 116. The suspended structure 410 may be disposed over PS 126A or PS 126B in place of the suspended structure 110.

[0053] Each suspension structure 410 includes an adjacent first suspension 417 and an adjacent second suspension 409. The adjacent first suspension 417 is defined by a first suspension extension 417A of the second structure 410B extending laterally beyond the upper surface of the first structure 410A. The first structure 410A is disposed above the upper surface 103 of a plurality of adjacent PSs 126A / 126B.

[0054] The adjacent second overhang 409 is defined by the sidewall 413 of the third structure 410C. At least the upper surface of the third structure 410C is wider than the bottom surface of the third structure 410C to form the sidewall 413 of the second overhang 409. The sidewall 413 of the third structure 410C forms the second overhang 409.

[0055] Figure 5is a schematic cross-sectional view of a suspended structure 510 according to an embodiment. The suspended structure 510 is illustrated without an accompanying substrate 102, metal-containing layer 104, PS 126A / 126B, OLED material 112, cathode 114, or encapsulation layer 116. The suspended structure 510 may be disposed over PS 126A or PS 126B in place of the suspended structure 110.

[0056] Each suspension structure 510 includes an adjacent first suspension 517, an adjacent second suspension 509, and an adjacent third suspension 522. The adjacent first suspension 517 is defined by a first suspension extension 517A of the second structure 510B extending laterally beyond the upper surface of the first structure 510A. The first structure 510A is disposed above the upper surface 103 of a plurality of adjacent PSs 126A / 126B.

[0057] The adjacent second overhang 509 is defined by the sidewall 513 of the third structure 510C. At least the upper surface of the third structure 510C is wider than the bottom surface of the third structure 510C to form the sidewall 513 of the second overhang 509. The sidewall 513 of the third structure 510C forms the second overhang 509.

[0058] The adjacent third overhang 522 is defined by the sidewall 515 of the fourth structure 510D. At least the bottom surface of the fourth structure 510D is wider than the bottom surface of the fourth structure 510D to form the sidewall 515 of the third overhang 522. The fourth structure 510D is disposed above the upper surface of the third structure 510C. The sidewall 515 of the fourth structure 510D forms the third overhang 522.

[0059] Figure 6 is a schematic cross-sectional view of a suspended structure 610 according to an embodiment. The suspended structure 610 is illustrated without an accompanying substrate 102, metal-containing layer 104, PS 126A / 126B, OLED material 112, cathode 114, or encapsulation layer 116. The suspended structure 610 may be disposed over PS 126A or PS 126B in place of the suspended structure 110.

[0060] Each suspension structure 610 includes an adjacent first suspension 617 and an adjacent second suspension 609. The adjacent first suspension 617 is defined by a first suspension extension 617A of the second structure 610B extending laterally beyond the upper surface 103 of the first structure 610A. The first structure 610A is disposed above the upper surface 103 of a plurality of adjacent PSs 126A / 126B.

[0061] The second structure 610B includes a lower sidewall 623 and an upper sidewall 624. The adjacent second overhang 609 is defined by the upper sidewall 624 of the second structure 610B. The upper surface 615 of the second structure 610B can be wider, equal to (as shown in the illustrated embodiment), or narrower than the bottom surface 607 of the second structure 610B. The second structure 610B further includes an inner plane 625. The upper surface 615 and the bottom surface 607 of the second structure 610B are wider than the second structure 610B at the inner plane 625. The lower sidewall 623 is formed between the bottom surface 607 and the inner plane 625 of the second structure 610B. The upper sidewall 624 is formed between the upper surface 615 and the inner plane 625 of the second structure 610B. The upper sidewall 613 of the second structure 610B forms the second overhang 609 and allows the upper sidewall 613 to shield the sidewall 623.

[0062] The encapsulation layer 116 is disposed below adjacent suspensions of the suspension structures 110, 210, 310, 410, 510, and 610. Therefore, the adjacent suspensions provide protection against moisture intrusion of the suspension structures 110, 210, 310, 410, 510, and 610. The adjacent suspensions establish a more complex moisture intrusion path due to the contact between the encapsulation layer 116 and the suspension structures 110, 210, 310, 410, 510, and 610. When moisture intrudes into the suspension structures 110, 210, 310, 410, 510, and 610, the encapsulation layer 116 establishes a barrier between the moisture and the suspension structures 110, 210, 310, 410, 510, and 610.

[0063] Figure 7 is a flow chart of a method 700 for forming a first sub-pixel circuit 100A or a second sub-pixel circuit 100B. FIG. 8A to FIG. 8D is a schematic cross-sectional view of a substrate 102 during a method 700 for forming a first sub-pixel circuit 100A or a second sub-pixel circuit 100B.

[0064] In operation 701, Fig. 8AAs shown, a first structure layer 802A and a second structure layer 802B are deposited over the substrate 102. The first structure layer 802A is disposed over the PS126A or the PS126B. The second structure layer 802B is disposed over the first structure layer 802A. The first structure layer 802A corresponds to the first structures 110A, 210A, 310A, 410A, 510A, and 610A of the suspended structures 110, 210, 310, 410, 510, and 610, respectively. The second structure layer 802B corresponds to the second structures 110B, 210B, 310B, 410B, 510B, and 610B of the suspended structures 110, 210, 310, 410, 510, and 610. The second structural layer 802B can also correspond to the third structure 110C, 210C, 310C, 410C, and 510C, the intermediate structure 323, and the fourth structure 210D and 510D. Resist 806 is set and patterned. Resist 806 is set above the second structural layer 802B. Resist 806 is a positive resist or a negative resist. The positive resist includes a portion of the resist, and when exposed to electromagnetic radiation, the portion is soluble in the resist developer applied to the resist after the pattern is written to the resist using electromagnetic radiation. The negative resist includes a portion of the resist, and when exposed to radiation, the portion will be insoluble in the resist developer applied to the resist after the pattern is written to the resist using electromagnetic radiation. The chemical composition of the resist 306 determines whether the resist is a positive resist or a negative resist.

[0065] In operation 702, Figure 8B As shown, the portion of the second structure layer 802B exposed by the resist 806 is removed. The second structure layer 802B exposed by the resist 806 can be removed by a dry etching process. In the illustrated embodiment, operation 702 forms the second structure 110B and the third structure 110C. In other embodiments, operation 702 can form: second structures 210B, 310B, 410B, 510B, and 610B; third structures 210C, 310C, 410C, and 510C; intermediate structure 323; and fourth structures 210D and 510D.

[0066] In operation 703, Figure 8CAs shown, the portion of the first structure layer 802A exposed by the resist 806 is removed. The first structure layer 802A exposed by the resist 806 can be removed by a wet etching process. In the illustrated embodiment, operation 703 forms the first structure 110A of the suspended structure 110. In other embodiments, operation 703 forms the first structures 210A, 310A, 410A, 510A, and 610A of the suspended structures 110, 210, 310, 410, 510, and 610, respectively. The etching selectivity between the materials of the second structure layer 802B corresponding to the second structure 110B and the third structure 110C and the first structure layer 802A corresponding to the first structure 110A, and the etching process for removing the exposed portions of the second structure layer 802B and the first structure layer 802A, are used to make the bottom surface 107 of the second structure 110B wider than the upper surface 105 of the first structure 110A to form the first suspension extension 117A of the first suspension 117.

[0067] In operation 704, Fig.8D As shown, the resist 806 is removed from the third structure 110C, thereby leaving the suspended structure 110 .

[0068] At operation 705, the OLED material 112, cathode 114, and encapsulation layer 116 of the first sub-pixel 108A are deposited. The shielding of the first suspension 117 and the second suspension 109 is used for evaporative deposition of each of the OLED material 112 and the cathode 114.

[0069] In summary, the embodiments described herein relate to a subpixel circuit that can be used in a display such as an organic light emitting diode (OLED) display and a method of forming the subpixel circuit. A plurality of adjacent pixels (PS) are arranged above a substrate. Each subpixel includes an adjacent first suspension, each first suspension being defined by a first suspension extension of a second structure extending laterally beyond an upper surface of the first structure. The first structure is arranged above the PS, and the second structure is arranged above the first structure. The adjacent second suspension is defined by a second suspension extension of a third structure extending laterally beyond an upper surface of the second structure. The third structure is arranged above the second structure. An encapsulation layer is arranged in the adjacent second suspension, thereby providing protection against moisture intrusion into the adjacent first suspension to improve the function of the subpixel circuit.

[0070] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope of the disclosure, which is to be determined by the claims that follow.

Claims

1. A device comprising: substrate; A plurality of suspension structures are arranged above the substrate, each of the suspension structures having: First structure; a second structure disposed above the upper surface of the first structure; adjacent first overhangs, each first overhang being defined by a first overhang extension of the second structure extending laterally beyond an upper surface of the first structure; a third structure, wherein the third structure is disposed above the second structure; as well as an adjacent second overhang; as well as A plurality of sub-pixels, each sub-pixel comprising: anode; an organic light emitting diode (OLED) material disposed over the anode; and A cathode is disposed above the OLED material.

2. The apparatus of claim 1, wherein the adjacent second overhang is defined by a second overhang extension of the third structure extending laterally beyond an upper surface of the second structure, and wherein the third structure is disposed above the upper surface of the second structure.

3. The apparatus according to claim 1, wherein the third structure further comprises: bottom surface; as well as an upper surface, wherein the upper surface is wider than the bottom surface; as well as A side wall is formed between the bottom surface and the upper surface, wherein the adjacent second overhang is defined by the side wall.

4. The apparatus according to claim 3, further comprising: A fourth structure, disposed above the upper surface of the third structure, comprises: a bottom surface; and an upper surface, wherein the upper surface is wider than the bottom surface; and a side wall formed between the bottom surface and the upper surface; and an adjacent third overhang, wherein the adjacent third overhang is defined by the side wall.

5. The apparatus according to claim 1, further comprising: Adjacent third suspensions, each of the third suspensions is defined by a third extension portion of a fourth structure extending laterally beyond an upper surface of the third structure, wherein the fourth structure is disposed above the upper surface of the third structure.

6. The apparatus of claim 1, further comprising an intermediate structure disposed above the second structure, wherein the third structure is disposed above the intermediate structure.

7. The apparatus according to claim 1, further comprising: A fourth structure, disposed above the upper surface of the third structure, comprises: a bottom surface; and an upper surface, wherein the upper surface is wider than the bottom surface; and a side wall formed between the bottom surface and the upper surface; and an adjacent third overhang, wherein the adjacent third overhang is defined by the side wall. 8 . The device of claim 1 , further comprising a pixel structure (PS) disposed over the substrate, and wherein the suspended structure is disposed over the PS.

9. The device of claim 7, wherein the PS comprises polyimide, silicon oxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (Si2N2O), magnesium fluoride (MgF2), or a combination thereof. 10 . The device of claim 1 , further comprising a pixel structure (PS) disposed over the substrate, and wherein the suspended structure is disposed over the PS.

11. The device of claim 9, wherein the PS comprises polyimide, silicon oxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (Si2N2O), magnesium fluoride (MgF2), or a combination thereof.

12. An apparatus comprising: substrate; A plurality of suspension structures are arranged above the substrate, each of the suspension structures having: First structure; A second structure is disposed above the upper surface of the first structure, the second structure comprising: Internal plane; upper surface; an upper side wall formed between the interior plane and the upper surface; a bottom surface; and a lower side wall formed between the interior plane and the bottom surface; adjacent first overhangs, each first overhang being defined by a first overhang extension of the second structure extending laterally beyond an upper surface of the first structure; and an adjacent second overhang formed by the upper sidewall; and A plurality of sub-pixels, each sub-pixel comprising: anode; an organic light emitting diode (OLED) material disposed over the anode; and A cathode is disposed above the OLED material.

13. The device of claim 12, wherein the upper sidewall is wider than the second structure at the interior plane. 14 . The device of claim 12 , further comprising a pixel structure (PS) disposed over the substrate, and wherein the suspended structure is disposed over the PS.

15. The device of claim 14, wherein the pixel structure (PS) comprises polyimide, silicon oxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (Si2N2O), magnesium fluoride (MgF2), or a combination thereof. 16 . The device of claim 12 , further comprising a pixel structure (PS) disposed over the substrate, and wherein the suspended structure is disposed over the PS.

17. The device of claim 15, wherein the PS comprises polyimide, silicon oxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (Si2N2O), magnesium fluoride (MgF2), or a combination thereof.

18. A method comprising: depositing a first structural layer and a second structural layer over the substrate; removing a portion of the second structure layer exposed by the resist to form a second structure and a third structure; removing a portion of the first structure layer exposed by the resist to form a first structure; removing the resist from the third structure; as well as Organic light emitting diode (OLED) materials, cathode, and encapsulation layers are deposited. The method of claim 18 , wherein the portion of the second structure layer is removed by a dry etching process.

20. The method of claim 18, wherein the portion of the first structure layer is removed by a wet etching process.

Images