CN110071162B

CN110071162B - display panel

Info

Publication number: CN110071162B
Application number: CN201910372281.6A
Authority: CN
Inventors: 张国瑞; 陈文泰; 陈文斌; 李庚益; 陈祖伟; 陈国光; 洪仕馨
Original assignee: AU Optronics Corp
Current assignee: AUO Corp
Priority date: 2018-06-22
Filing date: 2019-05-06
Publication date: 2021-08-06
Anticipated expiration: 2039-05-06
Also published as: CN110071162A

Abstract

A display panel, comprising a substrate, an active component layer disposed on the substrate, a first electrode disposed on the active component layer, an insulating layer disposed on the first electrode, a composite structure, an organic light-emitting layer, and a second electrode disposed on the organic light-emitting layer superior. The first electrode is electrically connected with the active device layer. The insulating layer has a first opening and sidewalls defining the first opening. The composite structure is arranged on the sidewall of the insulating layer, and includes a first inorganic layer and a first metal layer that are stacked. The first metal layer is electrically separated from the first electrode. The organic light-emitting layer is disposed in the first opening of the insulating layer.

Description

Display panel

Technical Field

The present invention relates to a display panel, and more particularly, to a display panel having an inorganic-metal composite structure.

Background

Light Emitting Diodes (LEDs) have advantages such as long life, small size, high shock resistance, low heat generation, and low power consumption, and thus have been widely used as indicators or light sources in home and various appliances.

The Ink Jet Printing (IJP) technology can improve the material utilization rate in the LED process to reduce the process cost, but before the Ink Jet coating, a bank (bank) corresponding to the pixel needs to be formed to define the area of each pixel. However, when the liquid drops are sprayed into the accommodating space formed by the retaining walls, the difference between the surface tension of the liquid and the adhesive force of the retaining walls leads to poor thickness uniformity of a film formed by a subsequent drying process, so that the brightness and the chromaticity around the pixel are obviously different from the center.

In addition, the material properties of the LED are more easily affected by moisture and oxygen to deteriorate, resulting in shrinkage of the LED film, which reduces the light emitting efficiency of the pixel structure and affects the display quality.

Disclosure of Invention

The invention provides a display panel with uniform brightness and good display quality.

The display panel comprises a substrate, an active component layer arranged on the substrate, a first electrode arranged on the active component layer, an insulating layer arranged on the first electrode, a composite structure, an organic light-emitting layer and a second electrode arranged on the organic light-emitting layer. The first electrode is electrically connected with the active component layer. The insulating layer has a first opening and a sidewall defining the first opening. The composite structure is arranged on the side wall of the insulating layer and comprises a first inorganic layer and a first metal layer which are stacked. The first metal layer is electrically separated from the first electrode. The organic light emitting layer is disposed in the first opening of the insulating layer.

In view of the above, the display panel according to an embodiment of the invention includes a composite structure of the first inorganic layer and the first metal layer stacked on each other, and the composite structure is disposed on the sidewall of the insulating layer and sandwiched between the insulating layer and the organic light emitting layer. Therefore, the composite structure can separate the organic light emitting layer from the insulating layer. The composite structure can prevent the gas released by the insulating layer from diffusing to the organic light-emitting layer, so that the organic light-emitting layer is not affected by moisture or oxygen to deteriorate or shrink the film, thereby providing excellent light-emitting efficiency and ensuring that the display panel has uniform brightness and good display quality.

In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.

Drawings

Fig. 1 is a partial cross-sectional view of a display panel according to an embodiment of the invention.

Fig. 2A is a schematic top view of a portion of a display panel according to an embodiment of the invention.

FIG. 2B is a cross-sectional view of the display panel along the line B-B' in FIG. 2A.

FIG. 2C is a cross-sectional view of the display panel along the section line C-C' in FIG. 2A.

[ notation ] to show

10: display panel

100: substrate

120: active component layer

130: a first electrode

140: insulating layer

141: upper surface of

142: first opening

142A: edge of a container

143: side wall

144: second opening

160: second electrode

180: protective layer

200A: composite structure

200B: composite line structure

210A: a first inorganic layer

210B: second inorganic layer

211A: outer edge

213A: inner edge

220A: a first metal layer

220B: second metal layer

300: organic light emitting layer

A-A ', B-B ', C-C ': section line

D: distance between two adjacent plates

H1: a first thickness

H2: second thickness

PS: spacer

Detailed Description

In the drawings, the thickness of layers, films, panels, regions, etc. have been exaggerated for clarity. Like reference numerals refer to like elements throughout the specification. It will be understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements present. As used herein, "connected" may refer to physical and/or electrical connections. Further, "electrically connected" or "coupled" may be such that there are additional elements between the two elements.

It will be understood that, although the terms first, second, third, etc. may be used herein to describe various components, elements, regions, layers and/or sections, these components, elements, regions, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a "first component," "member," "region," "layer" or "portion" discussed below could be termed a second component, member, region, layer or portion without departing from the teachings herein.

Unless defined otherwise, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present invention and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Fig. 1 is a partial cross-sectional view of a display panel according to an embodiment of the invention. Fig. 2A is a schematic partial top view of a display panel according to an embodiment of the invention, and fig. 2A schematically illustrates only some components for convenience of illustration and observation. FIG. 2B is a cross-sectional view of the display panel along the line B-B' in FIG. 2A. FIG. 2C is a cross-sectional view of the display panel along the section line C-C' in FIG. 2A. Referring to fig. 1 and fig. 2A, fig. 1 is a cross-section of the display panel 10 along a section line a-a' of fig. 2A, including a substrate 100, an active device layer 120, a first electrode 130, an insulating layer 140, a composite structure 200A, an organic light emitting layer 300, and a second electrode 160. In the embodiment, the protection layer 180 is disposed on the second electrode 160, but the invention is not limited thereto.

In the present embodiment, the active device layer 120 is disposed on the substrate 100. The substrate 100 may be made of glass, quartz, organic polymer, opaque/reflective material (e.g., conductive material, metal, wafer, ceramic, or other suitable material) or other suitable material. If a conductive material or metal is used, an insulating layer (not shown) is formed on the substrate 100 to prevent short circuit. The active device layer 120 may be, for example, an active device array (not shown), wherein the active device array includes a plurality of Thin Film Transistors (TFTs) (not shown). The thin film transistor is, for example, a low temperature polysilicon thin film transistor (LTPS) or an amorphous silicon thin film transistor (a-Si), but the invention is not limited thereto.

The first electrode 130 is disposed on the active device layer 120, and the first electrode 130 is electrically connected to the active device layer 120. The material of the first electrode 130 is a conductive material, such as aluminum (Al), silver (Ag), chromium (Cr), copper (Cu), nickel (Ni), titanium (Ti), molybdenum (Mo), magnesium (Mg), platinum (Pt), gold (Au), or a combination thereof. The first electrode 130 may have a single-layer, double-layer, or multi-layer structure. For example, the first electrode 130 may be a three-layer structure composed of ITO/Ag/ITO, but the invention is not limited thereto. In other embodiments, the first electrode 130 may also be a three-layer structure of Ti/Al/Ti or Mo/Al/Mo. In some embodiments, the first electrode 130 includes a reflective electrode, which may be a metal having a good reflectivity for visible light, such as aluminum, molybdenum, gold, or a combination thereof. In some embodiments, the first electrode 130 may be formed by Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), Atomic Layer Deposition (ALD), evaporation (VTE), Sputtering (SPT), or a combination thereof. In some embodiments, the first electrode 130 may serve as an anode (anode) of the organic light emitting layer 300, but the invention is not limited thereto.

In the present embodiment, the insulating layer 140 is disposed on the first electrode 130. The insulating layer 140 has a first opening 142 and sidewalls 143 defining the first opening 142. For example, before forming the organic light emitting layer 300, the first opening 142 of the insulating layer 140 is required to define the area of each pixel. In other words, the insulating layer 140 and the sidewalls 143 defining the opening 142 serve as the dam structure of the display panel 10. The organic light emitting layer 300 is disposed in the first opening 142 by an inkjet coating process. In some embodiments, the insulating layer 140 may be a hydrophobic material, such as a fluorine-containing negative photoresist, and is subjected to photolithography to form the sidewall 143 to define the first opening 142. In this way, the liquid applied to the first opening 142 by ink-jet can be well fixed therein.

In the present embodiment, the organic light emitting layer 300 is disposed in the first opening 142 of the insulating layer 140. The organic light emitting layer 300 has a light emitting structure as a pixel, for example. In some embodiments, the organic light emitting layer 300 may have a multi-layer structure including a Hole Injection Layer (HIL), a Hole Transport Layer (HTL), a light Emitting Layer (EL), and an Electron Transport Layer (ETL). Fig. 1 is shown in a one-layer structure for ease of illustration and clarity.

In some embodiments, the hole injection layer is made of a material such as copper phthalocyanine, star-like arylamines, polyaniline, polyethylene dioxythiophene, or other suitable materials. The material of the hole transport layer is, for example, a triarylamine, a cross-structure diaminobiphenyl, a diaminobiphenyl derivative, or other suitable materials. The light emitting layer may be a red organic light emitting pattern, a green organic light emitting pattern, a blue organic light emitting pattern, or a light emitting pattern of different colors (e.g., white, orange, yellow, etc.) generated by mixing light of respective spectrums. The material of the electron transport layer can be oxazole derivative and its dendrimer, metal chelate (e.g. Alq)₃) Azole compounds, diazanthracene derivatives, silicon-containing heterocyclic compounds, or other suitable materials.

In the present embodiment, in order to increase the utilization rate of the material and reduce the manufacturing cost of the display panel 10, the organic light emitting layer 300 may be formed by an Ink Jet Printing (IJP) process. For example, the hole injection layer, the hole transport layer and the light emitting layer may be formed on the first electrode 130 and in the first opening 142 by an inkjet coating process; the electron transport layer is formed on the light emitting layer by thermal evaporation process to reduce the driving voltage of the organic light emitting layer 300. Since the difference between the surface tension of the liquid and the suction force of the sidewall 143 of the insulating layer 140 may cause the drying process of the droplets to have uneven film thickness, the thickness of the organic light emitting layer 300 formed by the above process increases as it approaches the sidewall 143. For example, the thickness of the edge of the organic light emitting layer 300 at the intersection of the sidewall 143 and the first electrode 130 is the first thickness H1. The thickness of the organic light emitting layer 300 on the first electrode 130 in the first opening 142 is the second thickness H2. The organic light emitting layer 300 having the first thickness H1 is closer to the sidewall 143 than the second thickness H2, and thus the first thickness H1> the second thickness H2. Thus, the organic light emitting layer 300 has a concave arc surface with a thickness increasing from the center to the periphery in the cross section. As described above and shown in fig. 1, the thickness of the organic light emitting layer 300 increases toward the sidewall 143, and thus the thickness of the organic light emitting layer 300 closest to the sidewall 143 is greater than the thickness of the organic light emitting layer 300 close to the center point of the first opening 142 (e.g., the point farthest from the sidewall 143 in the first opening 142) in the direction perpendicular to the substrate 100. Based on the above, the second thickness H2 may be defined as the minimum thickness of the organic light emitting layer 300 on the first electrode 130 at the center point of the first opening 142, but the invention is not limited thereto. In essence, the second thickness H2 also includes a gradually increasing thickness of the organic light emitting layer 300 toward the junction of the composite structure 200A and the first electrode 130, that is, the second thickness H2 is a gradually increasing thickness from the center point of the first opening 142 toward the side wall 143 (but the second thickness H2 of the organic light emitting layer 300 does not overlap the composite structure 200A). In addition, the first thickness H1 is defined as the thickness of the organic light emitting layer 300 at the intersection between the sidewall 143 and the first electrode 130, and the composite structure 200A overlaps the intersection. In other words, the first thickness H1 is substantially the thickness of the organic light emitting layer 300 near the sidewall 143 and overlapping the composite structure 200A.

In some embodiments, the hole injection layer, the hole transport layer, the light emitting layer and the electron transport layer may also be formed by an inkjet coating process, which is not limited in the present disclosure.

In the present embodiment, the second electrode 160 is disposed on the organic light emitting layer 300. For example, the organic light emitting layer 300 is sandwiched between the first electrode 130 and the second electrode 160. In the embodiment, the second electrode 160 may be formed on the insulating layer 140 in a full-surface manner and overlap the first opening 142, the organic light emitting layer 300 and the first electrode 130, but the invention is not limited thereto. The material of the second electrode 160 may be a transparent conductor material, such as a metal oxide, e.g., indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, or indium germanium zinc oxide. In some embodiments, the second electrode 160 may be formed by Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), Atomic Layer Deposition (ALD), evaporation (VTE), Sputtering (SPT), or a combination thereof. In some embodiments, the second electrode 160 may serve as a cathode (cathode) of the organic light emitting layer 300.

Please refer to fig. 1 and fig. 2A, the display panel 10 of the present embodiment has a composite structure 200A disposed on the sidewall 143 of the insulating layer 140, and the composite structure 200A is sandwiched between the insulating layer 140 and the organic light emitting layer 300. The composite structure 200A includes a first inorganic layer 210A and a first metal layer 220A stacked one on another. In the present embodiment, the composite structure 200A partially covers the upper surface 141 of the insulating layer 140, and the composite structure 200A extends from the upper surface 141 to the first electrode 130. For example, the first inorganic layer 210A is disposed on the insulating layer 140, and the first metal layer 220A is disposed on the first inorganic layer 210A. The material of the first inorganic layer 210A is, for example, silicon oxide, silicon nitride, silicon oxynitride or other suitable materials, and can reach 10 deg.f ^-2～-4g/m²Water Vapor Transmission Rate (WVTR) of day. The material of the first metal layer 220A is, for example, a metal or a metal alloy, such as aluminum (Al), silver (Ag), chromium (Cr), copper (Cu), nickel (Ni), titanium (Ti), molybdenum (Mo), magnesium (Mg), platinum (Pt), gold (Au), or a combination thereof, or other suitable materials, and can further reduce the moisture passage rate to less than 10^-4g/m²And/day. In this way, under the operation of high temperature and high humidity, the gas (out bleeding) released from the insulating layer 140 does not diffuse into the organic light emitting layer 300. Therefore, the material of the organic light emitting layer 300 is not affected by moisture or oxygen to be altered or shrunk, so as to provide excellent light emitting efficiency, and the display panel 10 has uniform brightness and good display quality.

In this embodiment, the first inorganic layer 210A may have a single-layer or multi-layer structure, and the first metal layer 220A may also have a single-layer or multi-layer structure, which is not limited in the present invention. With the above arrangement, the water vapor passing rate of the composite structure 200A can be further reduced.

In the embodiment, the first inorganic layer 210A is partially disposed on the first electrode 130, and the first metal layer 220A is disposed on the first inorganic layer 210A to be electrically separated from the first electrode 130. The orthographic projection of the first metal layer 220A on the substrate 100 is located within the orthographic projection of the first inorganic layer 210A on the substrate 100. Thus, the first metal layer 220A and the first electrode 130 are separated by the first inorganic layer 210A, so as to ensure that the first metal layer 220A and the first electrode 130 are electrically separated, thereby avoiding short circuit.

Referring to fig. 1, 2A and 2B, the first inorganic layer 210A includes an outer edge 211A and an inner edge 213A. The outer edge 211A is disposed on the upper surface 141 of the insulating layer 140. The inner edge 213A is disposed on the first electrode 130. In the direction perpendicular to the substrate 100, a distance D is between the edge 142A and the inner edge 213A of the first opening 142, and the distance D is 5 to 10 micrometers. As such, the composite structure 200A may be partially disposed at the edge 142A of the first opening 142, i.e., the intersection of the sidewall 143 and the first electrode 130. Thus, the organic light emitting layer 300 formed at the intersection of the sidewall 143 and the first electrode 130 can overlap the composite structure 200A, so as to reduce the difference between the first thickness H1 of the organic light emitting layer 300 at the intersection and overlapping the composite structure 200A and the second thickness H2 of the organic light emitting layer at the first electrode 130. In other words, the thickness of the organic light emitting layer 300 in the first opening 142 can be more uniform and uniform as a whole, so that the luminance and chromaticity of the organic light emitting layer 300 are more uniform. Thereby, the display panel 10 may have uniform brightness and good display quality.

Under the above configuration, the light emitting area of the organic light emitting layer 300 can be further reduced from the edge 142A (i.e., the sidewall 143) of the first opening 142 to the center of the first opening 142 by 5 microns to 10 microns in the composite structure 200A. Thus, the light emitting range of the organic light emitting layer 300 can be further away from the sidewall 143, so that the film thickness in the light emitting range of the organic light emitting layer 300 is more uniform, and the luminance and the chromaticity are more uniform. Thereby, the display panel 10 may have uniform brightness and good display quality.

Referring to fig. 1, fig. 2A and fig. 2C, in the present embodiment, the display panel 10 further includes a composite circuit structure 200B disposed on the upper surface 141 of the insulating layer 140. The composite circuit structure 200B includes a second inorganic layer 210B and a second metal layer 220B stacked together. For example, the second inorganic layer 210B is disposed on the insulating layer 140, and the second metal layer 220B is disposed on the second inorganic layer 210B. The material of the second inorganic layer 210B is, for example, silicon oxide, silicon nitride, silicon oxynitride, or other suitable materials. The material of the second metal layer 220B is, for example, a metal or a metal alloy, such as aluminum (Al), silver (Ag), chromium (Cr), copper (Cu), nickel (Ni), titanium (Ti), molybdenum (Mo), magnesium (Mg), platinum (Pt), gold (Au), or a combination thereof or other suitable materials.

In the present embodiment, the first inorganic layer 210A and the second inorganic layer 210B are the same layer and can be fabricated at the same time. The first metal layer 220A and the second metal layer 220B are the same layer and can be fabricated at the same time. In the present embodiment, the composite wiring structure 200B is disposed around the composite structure 200A, and the composite structure 200A and the composite wiring structure 200B are separated from each other. For example, the composite structure 200A and the composite line structure 200B have a second opening 144 therebetween, and the second opening 144 exposes the upper surface 141 of the insulating layer 140. In the present embodiment, the composite structure 200A and the composite circuit structure 200B may be disposed by first forming an inorganic material layer (not shown) and a metal material layer (not shown), and then performing photolithography to form the second opening 144, so as to separate the composite structure 200A from the composite circuit structure 200B. Therefore, the composite structure 200A and the composite circuit structure 200B can be formed at the same time, so as to simplify the process and reduce the cost.

In the present embodiment, the second electrode 160 is electrically connected to the composite circuit structure 200B. Thus, the resistance of the second electrode 160 can be further reduced by the second metal layer 220B of the composite circuit structure 200B of the second electrode 160. Since the resistance of the second electrode 160 can be reduced, the resistance-capacitance loading (R-C loading) of the whole display panel 10 can be improved, and the performance of the display panel 10 can be improved.

In the present embodiment, the display panel 10 further includes spacers PS. The spacers PS are disposed on the second metal layer 220B of the composite circuit structure 200B. Since the insulating layer 140 may be a hydrophobic material (e.g., a fluorine-containing negative photoresist), the spacers PS are not easily fixed on the insulating layer 140, which may affect the reliability and uniformity of the display panel 10 and reduce the display quality. Under the above configuration, since the spacers PS and the metal material have good bonding force, the adhesion between the spacers PS and the second metal layer 220B can be improved. Thus, the spacers PS can be well fixed on the second metal layer 220B, and the reliability and the display quality of the display panel 10 are improved.

In summary, the display panel according to an embodiment of the invention includes a composite structure of the first inorganic layer and the first metal layer stacked together, and the composite structure is disposed on the sidewall of the insulating layer and sandwiched between the insulating layer and the organic light emitting layer. Therefore, the composite structure can separate the organic light emitting layer from the insulating layer. The first inorganic layer and the first metal layer in the composite structure can reduce the water vapor passing rate, so that the gas released by the insulating layer can be prevented from diffusing to the organic light-emitting layer. Therefore, the organic light-emitting layer is not affected by moisture or oxygen to deteriorate or shrink the film, so as to provide excellent light-emitting efficiency, and the display panel has uniform brightness and good display quality. In addition, the composite structure can ensure that the film thickness of the organic light-emitting layer is more uniform and uniform on the whole, and the brightness and the chromaticity of the organic light-emitting layer are more uniform. In addition, the composite structure can further define the light-emitting range of the organic light-emitting layer, so that the film thickness in the light-emitting range is more uniform, and further, the brightness and the chromaticity are more uniform.

The display panel of an embodiment of the invention further includes a composite circuit structure of the second inorganic layer and the second metal layer stacked on each other. The composite circuit structure can further reduce the resistance of the second electrode and improve the performance of the display panel. The composite circuit structure can also improve the adhesion between the spacer and the second metal layer. Therefore, the spacers can be well fixed on the second metal layer, and the reliability and the display quality of the display panel are improved.

Although the present invention has been described with reference to the above embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention.

Claims

1. A display panel, comprising:

a substrate;

an active component layer disposed on the substrate;

a first electrode disposed on the active component layer and electrically connected to the active component layer;

an insulating layer disposed on the first electrode and having a first opening and a sidewall defining the first opening;

A composite structure is disposed on the sidewall of the insulating layer, wherein the composite structure includes a first inorganic layer and a first metal layer that are stacked, and the first inorganic layer is disposed on the insulating layer and partially disposed On the first electrode, the first metal layer is located on the first inorganic layer, wherein the orthographic projection of the first metal layer on the substrate is located in the orthographic projection of the first inorganic layer on the substrate, and the first metal layer is located on the substrate. A metal layer is electrically separated from the first electrode;

an organic light-emitting layer disposed in the first opening of the insulating layer; and

a second electrode disposed on the organic light-emitting layer,

Wherein, the first inorganic layer includes an outer edge and an inner edge, the outer edge is arranged on the upper surface of the insulating layer, the inner edge is arranged on the first electrode, wherein in the direction perpendicular to the substrate, the There is a distance between the edge of the first opening and the inner edge, and the distance is 5 micrometers to 10 micrometers.

2 . The display panel of claim 1 , wherein the thickness of the organic light-emitting layer at the junction of the sidewall and the first electrode is a first thickness H1 , and the thickness of the organic light-emitting layer on the first electrode is 2 . The second thickness H2, and H1>H2.

3. The display panel of claim 1, wherein the composite structure partially covers an upper surface of the insulating layer, and the composite structure extends from the upper surface to the first electrode.

4 . The display panel of claim 1 , further comprising a composite wiring structure disposed on an upper surface of the insulating layer, the composite wiring structure comprising a second inorganic layer and a first inorganic layer that are stacked. 5 . Two metal layers, wherein the first inorganic layer and the second inorganic layer are the same film layer, and the first metal layer and the second metal layer are the same film layer.

5. The display panel of claim 4, wherein the second electrode is electrically connected to the composite wiring structure.

6. The display panel of claim 4, further comprising a spacer disposed on the second metal layer of the composite wiring structure.

7. The display panel of claim 4, wherein the composite wiring structure surrounds the composite structure, and the composite structure and the composite wiring structure are separated from each other.

8 . The display panel of claim 7 , wherein a second opening is formed between the composite structure and the composite wiring structure, and the second opening exposes the upper surface of the insulating layer. 9 .