OLED Display Substrate Tuning Layer Thickness Control
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Solution Overview
Problem
The existing methods for producing small-sized OLED products, such as Fine Metal Mask vapor deposition, are expensive and inefficient for stable mass production, and inkjet printing for large-sized OLEDs leads to low production efficiency, high costs, and low yield.
Innovation Solution
A display substrate with a base substrate, pixel driving layer, tuning layer, and organic light emitting diodes of varying thicknesses, where the thicknesses of the tuning and hole injection layers are negatively correlated across different colors, forming a microcavity structure using a multi-tone mask plate and inkjet printing to achieve efficient light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Fine Metal Mask vapor deposition is used to form organic electroluminescent layer, then small-sized OLED products can be produced, but production cost increases and mass production efficiency decreases
Solution Approach 1:
The patent changes the deposition parameters by using multi-tone mask plates with different light transmittance rates (first, second, and third light transmittance areas) to create varying thicknesses of the organic electroluminescent layer in different subpixels. This allows precise thickness control without requiring complex FMM processes, enabling both small-sized OLED production and improved mass production efficiency.
Solution Approach 2:
The patent uses a multi-tone mask plate that creates different thickness patterns through light transmittance variations, copying the desired thickness profile directly during deposition. This simplifies the manufacturing process compared to FMM while maintaining precision, resolving the contradiction between manufacturing precision and productivity.
2Manufacturing precision
If multi-tone mask plate with different light transmittance rates is used, then organic electroluminescent layer with different thicknesses can be formed in different subpixels, but process complexity increases
Solution Approach 1:
The mask plate is designed with different light transmittance rates in different areas (first, second, third light transmittance areas) to create local thickness variations in the organic electroluminescent layer. This allows precise control of layer thickness in different subpixels while using a single mask plate structure, balancing manufacturing precision with process simplicity.
3Area of stationary object
If inkjet printing is used for large-sized OLEDs, then production scalability improves, but production efficiency decreases and yield becomes low
Solution Approach 1:
The patent combines the advantages of vapor deposition (for efficiency and yield) with the ability to produce large-sized OLEDs by using multi-tone mask plates. This merging of approaches allows scalable production of large OLEDs while maintaining high production efficiency and yield, avoiding the drawbacks of inkjet printing.
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 enables stable mass production of OLEDs with improved light output, color gamut, and reduced production costs by accurately controlling the thicknesses of the tuning and hole injection layers, enhancing the efficiency and yield of the manufacturing process.
Implementation Method 1
The OLED has many advantages including self-illumination
Implementation Method 2
a microcavity in the respective one of the plurality of organic light emitting diodes is formed using the first electrode and the second electrode as reflective mirrors
Data Source
AI summary
A display substrate having an array of a plurality of subpixels is provided. The display substrate includes a base substrate; a pixel driving layer including a plurality of thin film transistors on the base substrate; a tuning layer on a side of the pixel driving layer away from the base substrate, thicknesses of the tuning layer being different in subpixels of different colors; and a plurality of organic light emitting diodes on a side of the tuning layer away from the pixel driving layer. A respective one of the plurality of organic light emitting diodes includes a hole injection layer, thicknesses of the hole injection layer being different in subpixels of different colors. The thicknesses of the tuning layer and the thicknesses of the hole injection layer are negatively correlated among the subpixels of different colors.