OLED Substrate Inorganic Pixel Definition Layer
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Solution Overview
Problem
The existing OLED substrate manufacturing process faces issues with incorrect stripping of the pixel definition layer during photoresist removal and pollution of the fine metal mask during evaporation, leading to potential short circuits and increased production costs.
Innovation Solution
A method involving the use of an inorganic film layer, such as silicon nitride or silicon oxide, for the pixel definition layer, which is patterned using a half-tone mask, and a photoresist layer is applied and stripped without damaging the layer, followed by sequential deposition of OLED layers using a fine metal mask to reduce contamination and improve mask efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a photoresist layer is used for the pixel definition layer in the TFT manufacturing process, then the pixel definition layer can be formed through standard photolithography, but the photoresist layer may be incorrectly stripped during the photoresist removal process, causing loss of the pixel definition layer and short circuits among anodes
Solution Approach 1:
The patent segments the pixel definition layer formation into two distinct parts: a support layer (inorganic material) and a pattern definition layer (photoresist material). The support layer provides structural integrity and resistance to stripping, while the pattern definition layer enables photolithography patterning. This segmentation allows the layer to withstand the photoresist stripping process without loss, preventing short circuits among anodes.
Solution Approach 2:
The patent employs a composite structure for the pixel definition layer, combining inorganic materials (such as silicon nitride or silicon oxide) with organic photoresist materials. The inorganic support layer provides mechanical strength and chemical stability during stripping, while the photoresist layer enables precise pattern transfer. This composite approach resolves the contradiction between ease of manufacture and reliability.
2Ease of manufacture
If the photoresist material is used for the pixel definition layer, then the layer can be easily patterned, but the photoresist material volatilizes during the evaporation process, polluting the fine metal mask and increasing cleaning frequency
Solution Approach 1:
The patent segments the pixel definition layer into a support layer (inorganic material) and a pattern definition layer (photoresist material). The inorganic support layer remains stable during the evaporation process and does not volatilize, thereby preventing pollution of the fine metal mask. The photoresist pattern definition layer can still be used for easy patterning, thus resolving the contradiction between ease of manufacture and harmful emissions.
Solution Approach 2:
The patent converts the potential harm of photoresist volatilization by separating the photoresist function from the structural support function. The inorganic support layer acts as a barrier that prevents photoresist vapors from reaching and polluting the fine metal mask during evaporation. This approach maintains the patterning benefits of photoresist while eliminating the pollution problem.
3Ease of manufacture
If the pixel definition layer is made of photoresist material, then it can be formed through standard processes, but the layer structure is incomplete, reducing its ability to protect anodes and substrate
Solution Approach 1:
The patent creates a composite pixel definition layer with an inorganic support layer providing mechanical strength and protective function, combined with a photoresist pattern definition layer enabling standard photolithography processes. The inorganic support layer compensates for the weakness of photoresist material, ensuring complete layer structure that can effectively protect anodes and substrate while maintaining ease of manufacture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively protects the anodes and substrate, reduces the risk of pixel definition layer loss, decreases the frequency of fine metal mask cleaning, and enhances the usage efficiency of the mask, resulting in improved OLED substrate performance.
Implementation Method 1
depositing an inorganic film layer on the substrate and the plurality of anodes
Implementation Method 2
stripping the photoresist layer on the second substrate
Implementation Method 3
sequentially forming a Hole Injection Layer, a Hole Transporting Layer, an organic light emitting layer, an Electron Transport Layer, an Electron Injection Layer and a cathode
Data Source
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AI summary
Provided are an OLED substrate and a manufacturing method thereof. The manufacturing method of an OLED substrate adopts an inorganic material to make a pixel definition layer, thereby reducing the risk of erroneously stripping the pixel definition layer in a process of stripping a photoresist material, reducing the risk of contaminating a fine metal mask in an evaporation process, and increasing utilization efficiency of the fine metal mask. In an OLED substrate manufactured by using the above manufacturing method of an OLED substrate, a pixel definition layer has an integral structure, such that an anode and a substrate thereunder can be effectively protected, thereby exhibiting favorable device performance.