Active Matrix OLED With Segmented Current Paths
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Solution Overview
Problem
Conventional stacked organic light emitting devices (SOLEDs) require high driving voltage, leading to increased power consumption and degradation of thin film transistors, while also having reduced luminous efficiency per unit area due to a single vertical current path.
Innovation Solution
The active matrix organic light emitting device features multiple emission layers stacked on an insulating substrate with first and second electrodes formed between and on the layers, respectively, allowing for separate current paths and independent driving of each emission layer, thereby reducing the required driving voltage and enhancing luminous efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple emission layers are stacked with a single vertical current path, then luminous efficiency per unit area is enhanced, but driving voltage increases more than twice compared to single emission layer devices
Solution Approach 1:
The patent divides the single vertical current path into multiple separate current paths by introducing first electrodes between adjacent emission layers. Each emission layer has its own independent current path from anode through the emission layer to cathode, allowing parallel current flow through multiple layers without voltage multiplication. This segmentation resolves the contradiction by maintaining high luminous efficiency through multiple layers while keeping driving voltage at conventional levels.
2Reliability
If high voltage is applied to form a single vertical current path in stacked emission layers, then current passes through all layers, but power consumption increases and thin film transistor characteristics are degraded
Solution Approach 1:
The patent segments the current path into multiple independent parallel paths, each passing through a separate emission layer. First electrodes are introduced between adjacent emission layers to create discrete current paths. This allows conventional voltage levels to drive current through multiple layers simultaneously via parallel paths, eliminating the need for high voltage and thereby reducing power consumption while preserving reliable current path formation.
Solution Approach 2:
The patent transitions from a single vertical current path (one-dimensional flow) to multiple vertical current paths distributed across the device area (multi-dimensional parallel flow). By introducing first electrodes at intermediate positions between emission layers, the current distribution is expanded from a single column to multiple columns, enabling parallel current flow that reduces power consumption while maintaining effective utilization of all emission layers.
3Productivity
If high voltage is used to drive stacked emission layers, then all layers can be activated, but thin film transistor characteristics are degraded
Solution Approach 1:
The patent segments the driving mechanism by providing separate current paths for each emission layer through first electrodes. This allows each emission layer to be driven independently at conventional voltage levels by the thin film transistor, avoiding the high voltage stress that degrades TFT characteristics. All emission layers remain activated through parallel current paths, resolving the contradiction between full layer activation and TFT reliability.
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 luminous efficiency per unit area without increasing the driving voltage, improving the performance and reducing power consumption compared to conventional SOLEDs.
Implementation Method 1
red, green, and blue (R, G, and B) organic emission layers are interposed between an anode electrode and a cathode electrode to emit light from the respective organic emission layers based on the voltage applied to the anode electrode and the cathode electrode
Data Source
AI summary
An active matrix organic light emitting device having a structure where a plurality of emission layers having each separate current path are stacked. In the active matrix organic light emitting device of the present invention, a plurality of emission layers are stacked on an insulating substrate. A thin film transistor is formed on the insulating substrate and is connected in common with a number of electrode layers to independently drive the plurality of emission layers.