Transparent Electrode Segmentation for Display Illumination
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Solution Overview
Problem
Existing illumination devices with line-shaped electrodes experience high electrical resistance, leading to increased moiré interference, complex patterning requirements, and potential electrode exposure, which complicates manufacturing and reduces efficiency.
Innovation Solution
The use of single film transparent electrodes covering the entire display region, with island-shaped light emitting elements in between, and an insulation film to prevent electrical shorts, along with a light shielding and reflective film configuration to manage light emission and reduce aperture ratio issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If line shaped electrodes are used, then the electrode structure is simple, but the electrical resistance becomes high
Solution Approach 1:
The electrode is divided into multiple finger-like arms that extend across the display region. These segmented arms are arranged in an interdigitated pattern with opposite polarity electrodes, creating multiple parallel conduction paths that reduce overall electrical resistance while maintaining a relatively simple fabrication process.
Solution Approach 2:
The electrode structure transitions from simple linear traces to two-dimensional finger-like arms that extend across the display area. This dimensional expansion creates multiple parallel conduction pathways, effectively reducing electrical resistance by distributing current across a larger effective area without significantly increasing fabrication complexity.
2Ease of manufacture
If line shaped electrodes are used, then manufacturing is simpler, but moiré interference occurs
Solution Approach 1:
The continuous electrode layer is segmented into multiple discrete finger-like arms with gaps between them. This segmentation eliminates the continuous periodic pattern that causes moiré interference, while the multiple arms still provide sufficient conduction paths. The segmented structure can be fabricated using standard photolithography techniques, maintaining ease of manufacture.
Solution Approach 2:
The electrode structure uses local segmentation where gaps are strategically placed between finger arms to eliminate moiré patterns in the display region, while maintaining continuous coverage in non-display regions for electrical connection. This localized application of segmentation resolves the moiré issue without compromising overall manufacturability.
3Ease of manufacture
If line shaped electrodes are used, then fabrication is easier, but electrode patterns become exposed
Solution Approach 1:
The electrode is segmented into finger-like arms that can be optimized for width and spacing. The wider finger arms provide sufficient conduction area while the gaps between them prevent pattern exposure. This segmented configuration allows for easier fabrication using standard lithography while eliminating the visual exposure of electrode patterns that would occur with finer line structures.
Solution Approach 2:
The electrode geometry parameters (width, spacing, length of finger arms) are optimized to balance conduction requirements with pattern hiding. By adjusting these parameters, the finger arms can be made wide enough to provide low resistance paths while being spaced sufficiently to prevent pattern exposure, achieving both fabrication ease and aesthetic requirements.
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 configuration reduces electrical resistance, prevents moiré interference, simplifies manufacturing, increases light emitting efficiency, and ensures effective light management, while maintaining low electrode visibility and high aperture ratios.
Implementation Method 1
Light emitting elements (organic electroluminescence elements) are provided between the arms of the positive electrode and the arms of the negative electrode
Data Source
AI summary
An illumination device includes: a substrate; a first transparent electrode covering approximately an entire surface of a display region of the substrate; a second transparent electrode which overlaps with the first transparent electrode when seen in plan view and covers approximately the entire surface of the display region; and a plurality of island shaped light emitting elements disposed between the first transparent electrode and the second transparent electrode. The first and second transparent electrodes are formed as single continuous films.