OLED Micro-Cavity Grooves for Optical Distance Control
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Solution Overview
Problem
The existing methods for forming micro-cavity structures in OLED display devices require multiple mask processes to set unique optical distances for each pixel, leading to reduced process efficiency due to the need for multiple reflective electrodes with different step heights.
Innovation Solution
The formation of grooves with varying depths in the planarizing layer allows for the creation of micro-cavity structures, where the reflective electrode is positioned within these grooves, enabling the adjustment of optical distances for each pixel based on the wavelength of light emitted, thereby simplifying the process and reducing the number of mask processes required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple mask processes are used to form reflective electrodes with different step heights for each pixel, then the optical distance can be adjusted for each pixel, but the process efficiency is reduced
Solution Approach 1:
The invention segments the optical path adjustment function into two parts: a common reflective electrode layer for all pixels, and individual transparent insulating layer thickness variations over each pixel. This segmentation allows the optical distance to be adjusted per pixel through the transparent layer thickness rather than requiring multiple mask processes for reflective electrodes, thereby maintaining precision while improving productivity
Solution Approach 2:
The transparent insulating layer serves as an intermediary element to adjust the optical distance. Instead of directly modifying the reflective electrode structure (which would require multiple mask processes), the invention uses the transparent insulating layer as a mediator whose varying thickness over different pixels achieves the desired optical distance adjustment while simplifying the manufacturing process
2Manufacturing precision
If unique transparent layers are formed for each pixel to set optical distances, then the optical distance can be optimized for each pixel, but the number of mask processes increases
Solution Approach 1:
The single transparent insulating layer performs multiple functions: it serves as an insulating layer for electrical isolation and simultaneously as an optical path adjustment element by having varying thickness over different pixels. This multi-functionality eliminates the need for separate transparent layers for each pixel and reduces the number of mask processes required
Solution Approach 2:
The transparent insulating layer has uniform material properties but varying local thickness to achieve different optical distances for different pixels. This local variation in thickness (rather than material composition) allows pixel-specific optical optimization while using a single unified layer structure, reducing manufacturing complexity
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 process efficiency by allowing the formation of micro-cavity structures with varying optical distances for each pixel in a single exposure process, improving the manufacturing efficiency of OLED display devices.
Implementation Method 1
light emitted from an organic emitting layer is repeatedly reflected between a reflective electrode and cathode electrode, and amplified by constructive interference
Implementation Method 2
light emitted from an organic emitting layer is repeatedly reflected between a reflective electrode and cathode electrode
Data Source
AI summary
Disclosed is an OLED display device. The OLED display device includes a substrate in which a plurality of pixels are defined, a thin film transistor formed in each of the pixels defined in the substrate, a passivation layer formed on the thin film transistor, a planarizing layer formed on the passivation layer and including a groove formed in an upper end portion of each pixel, a reflective electrode formed in the groove of the planarizing layer, an anode electrode formed on the reflective electrode, an organic emitting layer formed on the anode electrode, and a cathode electrode formed on the organic emitting layer.