OLED Series Connection via Conductive Bridge on Cover Lid
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Solution Overview
Problem
Existing OLED devices face challenges in operating at high voltages while maintaining long lifetime due to sensitivity to moisture and oxygen, and the manufacturing process for series-connected electroluminescent layer stacks is costly and labor-intensive, with potential damage from pressure and heat applied during interconnection.
Innovation Solution
The OLED device features multiple electroluminescent layer stacks connected in series via conductive bridges on the inner side of a rigid cover lid, which is sealed to the substrate with a gas-tight material to prevent moisture and oxygen ingress, reducing manufacturing effort and cost by eliminating the need for complex mask processes and minimizing mechanical impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple electroluminescent layer stacks are connected in series via laminated flexible interconnection sheets, then the short resistance is improved and higher operating voltages are enabled, but the lifetime of the OLED device deteriorates due to pressure and heat application during lamination
Solution Approach 1:
The patent replaces the mechanical lamination process with a non-contact conductive bridge formation method. Instead of applying pressure and heat through flexible interconnection sheets, the invention uses conductive bridges formed by printing or depositing conductive material directly between electrodes, eliminating mechanical stress and thermal exposure that damage the organic electroluminescent layers.
Solution Approach 2:
The patent introduces conductive bridges as an intermediary element to establish electrical connections between electroluminescent layer stacks. These bridges serve as the mediating structure that enables series connection without requiring direct contact or lamination of flexible sheets, thereby preventing moisture ingress while avoiding mechanical damage.
2Manufacturing precision
If mask processes are used to prepare patterns of multiple electroluminescent layer stacks, then the structuring precision is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent replaces complex mechanical mask processes with a printing or deposition-based conductive bridge formation method. This substitution eliminates the need for multiple masks and their precise alignment, reducing manufacturing complexity while maintaining the required structuring precision through direct material placement.
Solution Approach 2:
The patent performs preliminary formation of conductive bridges before final device assembly and testing. By establishing the electrical connections early in the manufacturing process through printing or deposition, the invention simplifies subsequent steps and reduces the overall manufacturing complexity compared to post-assembly mask processes.
3Ease of manufacture
If flexible interconnection sheets are laminated to establish series connections, then the manufacturing effort is reduced, but the encapsulation effectiveness deteriorates allowing moisture and oxygen diffusion
Solution Approach 1:
The patent replaces the lamination of flexible interconnection sheets with conductive bridges formed by printing or depositing conductive material. This substitution eliminates the need for flexible sheets that cannot provide effective encapsulation, while maintaining ease of manufacture through a simplified, direct material deposition process.
Solution Approach 2:
The conductive bridges serve as an intermediary structure that simultaneously provides electrical connection and encapsulation functionality. By forming these bridges as integral part of the device structure rather than adding separate flexible sheets, the invention achieves both electrical connectivity and effective barrier against moisture and oxygen diffusion.
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 solution enables OLED devices to operate at high voltages with improved lifetime performance and reduced manufacturing complexity, ensuring effective encapsulation and electrical connectivity while maintaining the integrity of the electroluminescent layers.
Implementation Method 1
the connection in series is established by connecting the first electrode of at least one of the electroluminescent layer stacks, preferably each of the electroluminescent layer stacks, involved in the serial connection via a conductive bridge to the second electrode of another electroluminescent layer stack involved in the serial connection
Implementation Method 2
the preparation of such layers stack might be performed with mask processes applying several different masks for the individual layers... Such laminated sheets might not be sufficient to prevent moisture and oxygen diffusing into the electroluminescent layer stack
Data Source
Figure 1(a)~1(b)
Figure 2~3
Figure 4(a)~4(b)
AI summary
The invention relates to OLED devices (1) operational at high voltages providing a good life time performance, which can be manufactured with reduced effort and costs. The organic electroluminescent device (1) comprising a substrate (2) carrying multiple electroluminescent layer stacks (3) connected in series each comprising a first and a second electrode (31, 33) and an organic light emitting layer stack (32) arranged between the first and second electrode (31, 33), a cover lid (4) sealed to the substrate (2) to encapsulate the electroluminescent layer stacks (3) providing a gap (5) between the electroluminescent layer stacks (3) and an inner side (41) of the cover lid (4), where the connection in series is established by connecting the first electrode (31) of at least one of the electroluminescent layer stacks (3) involved in the serial connection via a conductive bridge (6) to the second electrode (33) of another electroluminescent layer stack (3) involved in the serial connection, preferably the adjacent electroluminescent layer stack (3), where the conductive bridge (6) comprises an conductive path (62) arranged on the inner side (41) of the cover lid (4), a first electrical connection (61) connecting the first electrode (31) to the conductive path (62) and a second electrical connection (63) connecting the conductive path (62) with the second electrode (33) of the other electroluminescent layer stack (3), preferably the adjacent electroluminescent layer stack (3). The invention further relates to a method providing the organic electroluminescent device (1) with process steps leading to a reduced effort and costs.