OLED Panel Two-Layer Planarization for Backplate Flatness
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Solution Overview
Problem
Current OLED display panel technologies face limitations in flatness due to the inadequate planarization provided by existing planarization layers, which cannot meet the increasing requirements for resolution, aperture rates, and refresh frequencies, especially in top-emission inkjet printing applications.
Innovation Solution
A two-layer planarization structure is introduced, where the first planarization layer is made of polyimide or acrylic-based materials and the second of siloxane-based organic photoresist materials, with specific thickness ranges and a passivation layer, to enhance the flatness of the backplates without increasing the overall thickness, and the method involves sequential deposition and patterning of film layers, including an anode layer and via holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single planarization layer is used, then the device complexity is low, but the flatness of the backplate is insufficient for high-resolution top-emission IJP applications
Solution Approach 1:
The planarization layer is divided into two separate layers: a first planarization layer (initial planarization layer) and a second planarization layer (final planarization layer). Each layer has a specific thickness range (1-2.5 μm) and material composition, working together to achieve the required flatness for top-emission inkjet printing applications without excessive complexity
Solution Approach 2:
The patent specifies different material compositions for the two planarization layers. The first planarization layer uses one material system while the second planarization layer uses a different material system, creating a composite structure that optimizes both flatness achievement and process compatibility for high-resolution displays
2Reliability
If metal trace thickness is increased to meet higher resistance requirements, then the electrical performance improves, but the flatness provided by the planarization layer becomes insufficient
Solution Approach 1:
By segmenting the planarization function into two distinct layers, the patent can provide sufficient planarization capacity to accommodate thicker metal traces (required for higher resistance) while maintaining the flatness needed for precise inkjet printing. The cumulative thickness and material properties of both layers work together to compensate for the increased trace thickness
Solution Approach 2:
The patent optimizes parameters including the thickness of each planarization layer (1-2.5 μm range), material composition differences between layers, and the sequential deposition process to achieve the required flatness while supporting increased metal trace thickness for improved electrical reliability
3Loss of substance
If top-emission inkjet printing is used instead of bottom-emission vapor deposition, then raw material utilization rate increases to over 80%, but the requirements for backplate flatness become much higher
Solution Approach 1:
The two-layer planarization structure is specifically designed to meet the stringent flatness requirements of top-emission inkjet printing. By dividing the planarization function into initial and final layers, each optimized for specific thickness ranges and material properties, the patent achieves the high flatness necessary for precise inkjet material deposition while maintaining the material utilization advantages of IJP technology
Solution Approach 2:
The use of different materials in the two planarization layers provides optimized performance for inkjet printing applications. The composite structure delivers the superior flatness and surface properties required for high-precision inkjet deposition, enabling top-emission technology to achieve over 80% material utilization
Data Source
AI summary
An organic light-emitting diode (OLED) display panel and a method of manufacturing the same are disclosed. The OLED display panel includes a base substrate and a plurality of film layers sequentially deposited on a side of the base substrate in a stacked arrangement in a first direction. The plurality of film layers includes a first planarization layer configured to initially planarize an array substrate, and a second planarization layer configured to further planarize the array substrate. The first planarization layer and the second planarization layer are made of different materials.