Transparent OLED Pixel Electrode Overlap and Conduction Unit Design
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Solution Overview
Problem
Transparent organic light emitting display devices face issues with low transmittance and image distortion due to voltage drop in the opposite electrode and light scattering from conductive patterns, which are exacerbated as the device size increases.
Innovation Solution
The design includes a first substrate with transmitting regions and pixel regions separated by a transmitting region, thin film transistors, a passivation layer, pixel electrodes overlapping the transistors, a transparent opposite electrode, an organic emission layer, and a conduction unit between the substrates, with conductive lines crossing the transmitting regions to minimize conductive patterns and reduce scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the device size is increased, then the display area is improved, but voltage drop in the opposite electrode worsens
Solution Approach 1:
The opposite electrode is divided into multiple segments separated by insulating regions, with conduction units providing alternative current paths. This segmentation reduces the current density in each segment, thereby reducing voltage drop while maintaining large display area.
Solution Approach 2:
Conduction units are introduced as intermediary elements between the pixel electrodes and the opposite electrode. These conduction units serve as additional current paths that reduce the overall resistance and voltage drop in the opposite electrode, especially in large-area devices.
2Illumination intensity
If transparent thin film transistors and wires are used, then the transparency is improved, but image distortion worsens due to light scattering
Solution Approach 1:
Conductive patterns are extracted from the transmitting region and relocated to the pixel regions. This removal eliminates the light scattering sources from the transparent areas, preventing image distortion while maintaining the transparency provided by the thin film transistors and wires.
Solution Approach 2:
The conductive patterns are moved from the two-dimensional plane of the transmitting region to the pixel regions, effectively separating the light transmission function from the electrical conduction function in different spatial zones.
3Illumination intensity
If spaces between patterns are reduced, then the transmittance is improved, but light scattering worsens
Solution Approach 1:
Conductive patterns are extracted from the transmitting region entirely, eliminating the source of light scattering. This allows the spaces between remaining patterns to be minimized for high transmittance without introducing scattering from conductive elements.
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 enhances transmittance, reduces voltage drop, and prevents image distortion by optimizing the ratio of transmitting to pixel regions and using conductive materials to minimize the impact of conductive patterns on light transmission.
Implementation Method 1
an organic emission layer which is interposed between the pixel electrode and the opposite electrode so as to emit light
Implementation Method 2
a conduction unit interposed between the second substrate and the opposite electrode, having both ends contacting the second substrate and the opposite electrode, respectively, and formed of a conductive material
Data Source
AI summary
A transparent organic light emitting display device having improved transmittance comprises: a first substrate having a transmitting region and a plurality of pixel regions separated from each other by the transmitting region; thin film transistors positioned on a first surface of the first substrate and disposed in the pixel regions of the substrate; a passivation layer covering the thin film transistors; a plurality of pixel electrodes, formed on the passivation layer so as to be electrically connected to the thin film transistors, located in the pixel regions, and overlapping and covering the thin film transistors; an opposite electrode facing the pixel electrodes, formed to be able to transmit light, and located in the transmitting region and the pixel regions; an organic emission layer interposed between the pixel electrode and the opposite electrode to emit light; a second substrate facing the opposite electrode and bonded to the first substrate; and a conduction unit interposed between the second substrate and the opposite electrode, and having both ends contacting the second substrate and the opposite electrode.