OLED Source-Drain Electrode Stack Reduces Thickness
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Solution Overview
Problem
The manufacturing process of organic light emitting display devices is complex and prone to defects due to the need for precise photolithography and multiple operations, leading to increased thickness and variability in light emitting and electric characteristics.
Innovation Solution
The organic light emitting display device incorporates a substrate with a thin film transistor, wiring portion, and intermediate layer, where the source/drain electrodes are sequentially stacked with Ti, Ag, and high work function materials, and the wiring portion shares the same material as the first conductive layer, simplifying the structure and reducing thickness, and eliminates the need for additional pixel electrodes and separate capacitor electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography method using mask is used to form minute patterns, then desired patterns can be formed on thin films, but the manufacturing process becomes more complicated and time-consuming with increased number of operations
Solution Approach 1:
The patent extracts and eliminates the mask formation step from the photolithography process. By using direct patterning methods where patterns are formed without requiring mask fabrication, alignment, and removal steps, the complex multi-step photolithography process is simplified while maintaining pattern formation precision.
Solution Approach 2:
The patent performs preliminary patterning of the organic light emitting layer and electrode materials directly during the deposition process. By pre-planning the pattern design and using shadow masking or direct writing deposition techniques, the need for subsequent mask-based photolithography steps is eliminated, reducing process complexity.
2Manufacturing precision
If multiple photolithography processes using masks are performed, then desired patterns can be formed, but the manufacturing time increases and defect control becomes more difficult
Solution Approach 1:
The patent combines multiple patterning operations into a single deposition process. By using multi-layer co-deposition or sequential deposition with in-situ patterning, patterns for different layers are formed simultaneously or in fewer steps, eliminating the need for multiple separate photolithography cycles and significantly reducing manufacturing time.
3Device complexity
If thin films are stacked to form multiple layers, then desired device structure can be achieved, but the total thickness of the device increases
Solution Approach 1:
The patent employs nested layer structures where thinner functional layers are deposited within or between other layers. The organic light emitting layer, electrode layers, and encapsulation layers are arranged in a nested configuration that achieves the required device functionality while minimizing overall thickness through optimized layer integration.
Solution Approach 2:
The patent uses ultra-thin film technologies for all encapsulation and functional layers. By employing atomic layer deposition (ALD) or molecular beam epitaxy (MBE) to create nanometer-scale thin films with precise control, the device achieves its structural requirements with minimal thickness, preventing device thickening despite multiple layered components.
4Ease of operation
If conventional electrode and wiring configurations are used, then device functionality is achieved, but light emitting characteristics and electric characteristics vary
Solution Approach 1:
The patent systematically optimizes the material composition, thickness, and work function parameters of electrode and wiring layers. By controlling deposition conditions, layer thicknesses, and material ratios during fabrication, the electrical and optical characteristics are standardized across devices, reducing variability and improving reliability while maintaining full device functionality.
Data Source
AI summary
An organic light emitting display device with a simplified manufacturing process and improved electrical characteristics, along with a method of manufacturing the device, are disclosed. The device includes: a substrate having a display area and a non-display area; a thin film transistor (TFT) in the display area; a wiring portion in the non-display area; an intermediate layer electrically connected to the TFT and including an organic light emitting layer; and a counter electrode on the intermediate layer. The TFT includes an active layer, a gate electrode, and source/drain electrodes electrically connected to the active layer. The source/drain electrodes include a first conductive layer, a second conductive layer, and a third conductive layer that are sequentially stacked. The wiring portion includes the same material as the first conductive layer. One of the source/drain electrodes is longer than the other, to function as a pixel electrode, and is electrically connected to the intermediate layer.