OLED Micro-Screen Bilayer Stack Etching for Thickness Control
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Solution Overview
Problem
The existing methods for manufacturing organic light-emitting diode (OLED) microscreens face challenges in precision control of spacer layer thicknesses due to successive deposits, leading to operational inefficiencies and complexity, particularly in the deposition and etching phases which require thermal annealing, affecting the ease of implementation and operation time.
Innovation Solution
A method involving the formation of bilayer stacks of conductive transparent oxides, which allows for selective etching without thermal annealing interruptions, enabling precise control of thicknesses and simplifying the manufacturing process by linking deposition and etching phases directly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If successive deposits are used to form the spacer layer portions, then the optical resonator can be formed with different thicknesses for red, green and blue sub-pixels, but the precision control of thicknesses deteriorates
Solution Approach 1:
The spacer layer is divided into three separate portions (first, second, and third portions) with different thicknesses, each corresponding to a specific sub-pixel color (red, green, blue). This segmentation allows each portion to be independently optimized for its required thickness while maintaining overall manufacturing simplicity through the use of a single material layer.
2Manufacturing precision
If thermal annealing is applied to amorphous ITO layers to form polycrystalline ITO, then the thickness control of spacer layer is improved, but the operation time increases due to process interruptions
Solution Approach 1:
The thermal annealing step is completely removed from the manufacturing process. Instead of depositing amorphous ITO and then annealing it to form polycrystalline ITO, the invention directly deposits polycrystalline ITO in a single step, extracting the time-consuming annealing process while maintaining the desired material properties and thickness control.
3Manufacturing precision
If multiple deposition and etching phases are chained with thermal annealing, then the thickness precision is maintained, but the process complexity increases
Solution Approach 1:
Multiple deposition and etching phases that were previously separated by thermal annealing steps are merged into a single continuous process. The invention deposits all necessary spacer layer portions in one go and performs etching operations without intermediate annealing, thereby reducing process complexity while maintaining thickness precision through the inherent stability of the direct deposition method.
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 approach enhances precision in controlling the thicknesses of the bilayer stacks, reducing operation time and improving ease of implementation, while maintaining the optical resonator's functionality for red, green, and blue light transmission.
Implementation Method 1
The range of filtered wavelengths is determined by the thicknesses of the first, second and third portions of the spacer layer making it possible to adjust the thickness of the optical cavity (delimited by the first and second electrodes) so that the optical resonator respectively allows the transmission of red, green and blue light
Data Source
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AI summary
This process comprises the following successive steps: a) providing a substrate (1) having a first structured electrode (E1); b) successively forming first and second bilayer stacks on the first structured electrode (E1), each bilayer stack successively comprising first and second layers (20, 21; 30, 31) made of transparent conductive oxides that can be selectively etched; c) etching the second bilayer stack for an area intended to accommodate a blue sub-pixel (PB) and for an area intended to accommodate a green sub-pixel (PV); d) etching the first bilayer stack for the area intended to accommodate the blue sub-pixel (PB); e) forming a stack (5) of organic electroluminescent layers, configured to emit white light; f) forming a second electrode (E2) on the stack (5) of organic electroluminescent layers so as to obtain an optical resonator with the first electrode (E1).