OLED Pixel Defining Layer Structure for Uniform Color Emission
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Solution Overview
Problem
Current OLED substrate manufacturing techniques face challenges in achieving uniform light-emitting layer formation and preventing color mixture between adjacent regions, leading to inconsistent light emission and reduced purity.
Innovation Solution
The array substrate design features a pixel defining layer with specific thickness and width ratios for its strips and sub-portions, combined with an inkjet printing process, to create distinct openings for light-emitting layers, ensuring uniform ink distribution and separation of colors, thereby forming a one-piece structure with improved film formation uniformity and light purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional pixel defining structures are used, then manufacturing is simpler, but light-emitting layer uniformity deteriorates and color mixture occurs between adjacent regions
Solution Approach 1:
The pixel defining layer is segmented into multiple functional components: defining strips (for isolation), defining portions (for opening definition), first sub-portions (for ink distribution control), and second sub-portions (for structural support). This segmentation allows each component to perform its specific function optimally, preventing color mixture while ensuring uniform light-emitting layer formation through the controlled thickness variations.
Solution Approach 2:
Different regions of the pixel defining layer are given different thicknesses to perform different functions: the defining strips have greater thickness for effective isolation, while the first sub-portions have reduced thickness (5-10% of defining strip thickness) to control ink distribution, and second sub-portions have even smaller thickness for structural support. This local quality variation resolves the contradiction by optimizing each region for its specific purpose.
2Manufacturing precision
If uniform pixel defining structures are used, then manufacturing is easier, but ink distribution uniformity deteriorates leading to inconsistent light emission
Solution Approach 1:
The thickness parameter of the pixel defining layer is varied systematically across different regions: defining strips maintain greater thickness, first sub-portions are reduced to 5-10% of the defining strip thickness, and second sub-portions are further reduced. This parameter change creates a thickness gradient that guides ink flow and distribution during the inkjet printing process, ensuring uniform light-emitting layer formation while remaining compatible with standard manufacturing processes.
3Area of stationary object
If adjacent light-emitting regions are closely spaced, then substrate area utilization improves, but color mixture between adjacent regions increases
Solution Approach 1:
The pixel defining layer introduces a vertical dimension (thickness variation) to solve the horizontal color mixture problem. By creating defining strips with greater thickness that extend into the vertical dimension, the structure provides effective isolation between adjacent light-emitting regions, preventing color mixture while allowing close spacing and maximizing substrate area utilization.
Data Source
AI summary
An array substrate includes a base and a pixel defining layer and light-emitting layers that are disposed on the base. The pixel defining layer includes defining strips extending in a first direction and defining portions extending in a second direction, the defining strips and the defining portions define openings, defining portions located between two adjacent defining strips are spaced apart in the first direction, a defining portion includes at least two second sub-portions and first sub-portion(s) connected to the two adjacent defining strips through the at least two second sub-portions, thickness of a defining strip is greater than a thickness of a first sub-portion, and the thickness of the first sub-portion is greater than a thickness of a second sub-portion. Portion(s) of a light-emitting layer is disposed in a corresponding opening, and at least two light-emitting layers between the two adjacent defining strips are connected to form a one-piece structure.