Light-Emitting Device Shield Electrode Crosstalk Prevention
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Solution Overview
Problem
The crosstalk phenomenon occurs in light-emitting panels with tandem elements, where current leaks between adjacent sub-pixels due to highly conductive intermediate layers or carrier-injection layers, leading to inefficient luminance and reduced lifetime of organic EL elements.
Innovation Solution
A light-emitting device is designed with an insulating layer, lower electrodes, a partition, and a stacked-layer film containing a light-emitting layer and a conductive layer, along with a third electrode that separates the lower electrodes and is formed using the same layer as the first lower electrode, to prevent current leakage and crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a highly conductive intermediate layer is provided between light-emitting units in a tandem element, then driving voltage is decreased, but current leaks to adjacent sub-pixels causing crosstalk phenomenon
Solution Approach 1:
A third electrode (shield electrode) is introduced as an intermediary between adjacent lower electrodes to block current leakage. This shield electrode is formed using the same layer as the lower electrodes and is positioned to prevent direct current paths between neighboring sub-pixels while allowing the highly conductive intermediate layer to maintain low driving voltage.
Solution Approach 2:
The solution adds a spatial dimension by introducing the third electrode that extends in a direction perpendicular to the current flow between lower electrodes. This creates an additional barrier dimension that blocks lateral current leakage without affecting the vertical current flow needed for light emission.
2Illumination intensity
If high luminance is achieved by increasing current density, then luminance increases, but deterioration of organic EL elements accelerates reducing lifetime
Solution Approach 1:
The light-emitting element is divided into multiple light-emitting units stacked in series (tandem structure). This segmentation allows the total luminance requirement to be distributed across multiple units, each operating at lower current density, thereby reducing deterioration while maintaining high overall luminance output.
3Productivity
If tandem elements are stacked to achieve high luminance with small current, then luminance per current increases, but electrical resistance increases making current more prone to leak to adjacent pixels
Solution Approach 1:
The third electrode serves as a shield intermediary that blocks lateral current leakage paths between adjacent tandem elements. By positioning this electrode between lower electrodes of neighboring sub-pixels, it prevents current from leaking through the highly conductive intermediate layers while maintaining the efficient tandem structure for high luminance output.
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 solution effectively inhibits the crosstalk phenomenon, allowing for higher luminance without increasing current density and extending the lifetime of light-emitting elements by isolating current flow between sub-pixels.
Implementation Method 1
a light-emitting layer containing a light-emitting substance
Data Source
AI summary
Occurrence of a crosstalk phenomenon in a light-emitting device is inhibited. A light-emitting device including an insulating layer 416; a first lower electrode 421a formed over the insulating layer; a second lower electrode 421b formed over the insulating layer; a partition 418 formed over the insulating layer and positioned between the first lower electrode and the second lower electrode; a stacked-layer film 423 which is formed over the first lower electrode, the partition, and the second lower electrode and includes a light-emitting layer containing a light-emitting substance and a layer having higher conductivity than that of the light-emitting layer; an upper electrode 422 formed over the stacked-layer film; and a shield electrode 419 which is formed under the partition and does not overlap with the first lower electrode and the second lower electrode.