OLED Spatially Isolated Light-Emitting Areas via Insulating Bridges
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Solution Overview
Problem
Existing OLED manufacturing techniques restrict the geometrical shapes of light-emitting areas to only certain forms, as each cathode area must be electrically connected to a contact pad on the edge, limiting the design flexibility and resulting in visible seams when combining separate OLED elements.
Innovation Solution
The method involves applying an insulating bridge between a contact pad and a spatially isolated region of the second electrode, followed by a conductor to establish an electrical connection, allowing for any desired shape of light-emitting areas without the need for direct connection to edge cathode pads, achieved through selective removal of device layers and use of printing techniques for precise application of insulating and conductive materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If shadow mask is used to apply the second electrode to create spatially isolated light-emitting areas, then light emission can be restricted to certain areas, but only certain geometrical shapes can be realised and the manufacturing process becomes more complex
Solution Approach 1:
The second electrode is segmented into spatially isolated regions, each electrically connected to contact pads through separate conductive paths. This segmentation allows independent shaping of light-emitting areas without requiring complex shadow masks, as each region can be defined by its own conductor trace pattern on the flexible substrate.
Solution Approach 2:
The patent transitions from planar shadow mask patterning to three-dimensional routing of conductive paths on a flexible substrate. By utilizing the z-dimension (thickness) and flexible substrate conformability, conductors can route around obstacles and connect isolated electrode regions to contact pads without requiring complex two-dimensional mask patterns.
2Shape
If separate OLED elements are combined to obtain desired light-emitting shape, then geometrical flexibility is improved, but visible seams appear between elements due to encapsulation
Solution Approach 1:
Multiple isolated second electrode regions are merged into a single continuous OLED structure on one flexible substrate. The conductive paths and insulating bridges integrate these regions seamlessly, eliminating the need for separate encapsulated elements and their associated visible seams while maintaining the ability to create complex overall shapes.
Solution Approach 2:
Insulating bridges serve as intermediaries between isolated second electrode regions and contact pads, enabling electrical connection without physical contact. This intermediary structure allows the OLED to maintain a uniform encapsulated appearance without visible seams, as the connections are made through the flexible substrate rather than requiring separate element interfaces.
3Ease of manufacture
If direct connection to edge cathode pads is required, then electrical connection is simple, but light-emitting areas must be within direct reach of edge pads limiting design flexibility
Solution Approach 1:
The conductive paths are made flexible and dynamic, able to route through three-dimensional space on the flexible substrate rather than being constrained to straight lines on a rigid plane. This dynamic routing capability maintains electrical connection simplicity while enabling light-emitting areas to be positioned anywhere on the substrate, greatly enhancing design flexibility.
Solution Approach 2:
Insulating bridges with integrated conductors serve as intermediaries that extend the reach of contact pads into the interior of the OLED device. These intermediaries carry electrical connections from edge contact pads to isolated second electrode regions located anywhere on the substrate, eliminating the constraint that light-emitting areas must be within direct reach of edge pads.
Data Source
AI summary
The invention describes a method of forming spatially isolated light- emitting areas (R1, R2, R3) on a common substrate (11) of an OLED device (1) comprising a plurality of device layers (12, 15, 16), which device layers (12, 15, 16) comprise an active layer (15) enclosed between a first electrode (12) and a second electrode (16), which method comprises the steps of applying an insulating bridge (20) between a contact pad (13) and the isolated region (R1, R2, R3) of the second electrode (16); and subsequently applying a conductor (30) from a contact pad (13) to the isolated region (R1, R2, R3) of the second electrode (16) to form an electrical connection between the contact pad (13) and the isolated region (R1, R2, R3). The invention further describes an OLED device (1) comprising a number of spatially isolated light-emitting areas (R1, R2, R3) on a common substrate (11), wherein a plurality of device layers (12, 15, 16) of the OLED device initially comprises an active layer (15) enclosed between a first electrode (12) and a second electrode (16), and wherein the OLED device (1) comprises at least one spatially and electrically isolated region (R1, R2, R3) of the second electrode (16); an insulating bridge (20) applied between a contact pad (13) and the isolated region (R1, R2, R3) of the second electrode (16); and a conductor (30) applied onto the insulating bridge (20) for electrically connecting the contact pad (13) and the isolated region (R1, R2, R3) of the second electrode (16).