Multi-Stage Recessed Electrode Structure for OLED Light Efficiency
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Solution Overview
Problem
Organic light emitting display devices, particularly in head-mounted displays, face challenges in improving light efficiency due to restrictive light emitting areas, which affects the ability to achieve high resolution and luminance.
Innovation Solution
A display device design featuring a substrate with subpixel areas, a circuit element layer, an insulating layer with recessed portions, a reflective electrode, and multiple stages of electrodes to enhance light emission efficiency, including a recessed portion and reflective electrode structure that reduces the distance between the light emitting position and the reflective electrode, thereby improving light path efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the light emitting area is increased to improve light efficiency, then the luminance and resolution are improved, but the device size and complexity increase
Solution Approach 1:
The contact hole is divided into multiple stages (first stage, second stage, third stage) with different widths, creating a stepped structure. This segmentation allows the light emitting area to be increased through multiple levels rather than requiring a single large area, thereby improving light efficiency while maintaining a compact overall structure.
Solution Approach 2:
The contact hole structure transitions from a two-dimensional planar area to a three-dimensional stepped structure by adding vertical depth with multiple stages. This dimensional change enables the light emitting area to be effectively increased through the depth dimension, improving light efficiency without proportionally increasing the horizontal device footprint.
2Loss of energy
If the contact hole size is increased to improve light efficiency, then more light can be emitted, but the manufacturing precision and control become more difficult
Solution Approach 1:
The contact hole is segmented into multiple stages with progressively changing widths. This segmentation breaks down the complex task of forming a single large contact hole into multiple simpler steps, each with controlled width transitions. The multi-stage structure allows for better manufacturing control compared to forming a single large contact hole, as each stage can be precisely controlled during the fabrication process.
Solution Approach 2:
Different stages of the contact hole have different widths tailored to specific functional requirements. The first stage has a wider opening for light emission, while subsequent stages have progressively narrower widths for structural support and electrical connection. This local variation in quality (width) optimizes both light efficiency and manufacturing control in different regions of the same structure.
3Loss of energy
If the distance between the light emitting position and reflective electrode is reduced to improve light path efficiency, then light efficiency increases, but the structural design complexity increases
Solution Approach 1:
The electrode structure is segmented into multiple stages corresponding to the contact hole stages. This segmentation creates a stepped electrode configuration that follows the multi-level contact hole structure, enabling the light emitting position to be brought closer to the reflective electrode through the vertical staging while maintaining structural integrity and electrical functionality.
Solution Approach 2:
The multi-stage contact hole structure with reflective electrode and first electrode is nested within the insulating layer. Each stage is contained within the overall device structure, with the electrodes and reflective surfaces nested at different depth levels. This nesting arrangement achieves reduced distance between light emitting position and reflective electrode while integrating the complexity into a compact nested configuration.
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
The design significantly enhances light efficiency by up to 46% to 70% compared to traditional designs, leading to improved luminance and resolution in organic light emitting display devices, especially in head-mounted displays.
Implementation Method 1
a reflective electrode provided on the insulating layer and provided in the recessed portion
Data Source
AI summary
A display device includes a substrate provided with a plurality of subpixel areas, a circuit element layer provided on the substrate and provided with a transistor for each subpixel area, an insulating layer provided on the circuit element layer and provided with a recessed portion formed to overlap the transistor, a reflective electrode provided on the insulating layer and provided in the recessed portion, a first electrode provided on the reflective electrode while being overlapped with the recessed portion, an organic light emitting layer provided on the first electrode, a bank provided between the subpixel areas while covering an end of the first electrode, and a second electrode provided on the organic light emitting layer, wherein the recessed portion, the reflective electrode and the first electrode may be provided with N stages, wherein N is an integer greater than 1, whereby light efficiency may be improved.