OLED Backsheet Insulation via Laser-Cut Patches and Adhesive Barriers
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Solution Overview
Problem
Encapsulated OLED devices are prone to electrical shorting due to potential contact between conductive patches and internal metal foils, especially when burrs on patch edges puncture the insulating polymer layer or when conductive adhesives spread and make contact with the metal foil, leading to reliability issues, especially in flexible and large-area applications.
Innovation Solution
The use of precut non-conductive washers and viscous insulating materials to isolate the internal patches and conductive adhesives from the metal foil, along with laser-cutting to prevent burrs, and applying insulative epoxy to cover exposed metal edges, reduces the risk of electrical shorting by creating additional insulating barriers and preventing mechanical deformation during the assembly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive patches are used to establish electrical pathways through openings in the backsheet, then electrical connectivity is achieved, but the risk of electrical shorting increases due to potential contact with internal metal foil
Solution Approach 1:
The patent introduces an insulating adhesive layer as an intermediary substance between the conductive patch and the metal foil. This adhesive layer acts as a mediator that allows the conductive patch to maintain electrical connectivity while preventing direct contact with the metal foil, thereby eliminating the electrical shorting risk. The insulating adhesive is applied to the backsheet surface and fills the opening, creating a controlled pathway that isolates conductive elements.
Solution Approach 2:
The patent applies the insulating adhesive layer before positioning the conductive patch. This preliminary action ensures that the insulating barrier is already in place before the conductive element is introduced, preventing any potential contact with the metal foil from the outset. The adhesive is cured or set in advance to establish a reliable insulating barrier prior to final assembly.
2Ease of manufacture
If burrs are present on patch edges to facilitate insertion, then assembly ease is improved, but the insulating polymer layer may be punctured causing shorting
Solution Approach 1:
The patent applies the insulating adhesive layer beforehand to cushion and protect the metal foil and insulating polymer layer from potential damage by burrs on the conductive patch edges. This prior cushioning ensures that even if burrs are present, they cannot puncture through the adhesive barrier to reach the metal foil, thus maintaining insulating layer integrity while allowing easy assembly.
3Strength
If conductive adhesive is used to bond components, then bonding strength is improved, but the adhesive may spread and contact metal foil causing shorting
Solution Approach 1:
The patent segments the adhesive application into two distinct functional zones: a conductive adhesive layer for bonding components together, and an insulating adhesive layer for electrical isolation. The conductive adhesive is applied in controlled amounts and contained within boundaries defined by the insulating adhesive layer, preventing it from spreading to contact the metal foil. This segmentation allows both strong bonding and electrical isolation to coexist.
4Reliability
If the backsheet is made impermeable for hermetic sealing, then moisture and oxygen protection is improved, but electrical pathways require openings that create shorting risks
Solution Approach 1:
The patent makes the insulating adhesive layer multi-functional: it serves as both the hermetic sealant that protects against moisture and oxygen, and as the electrical insulator that prevents shorting. This single material performs multiple critical functions, eliminating the need for separate sealing and insulating layers, thereby simplifying the overall device complexity while maintaining both hermetic sealing and electrical isolation.
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 approach significantly decreases the likelihood of electrical shorting, enhancing the reliability and durability of flexible OLED panels by maintaining the integrity of the insulating layers and preventing unintended contact between conductive components, thus ensuring a more reliable and flexible light source assembly.
Implementation Method 1
laser-cutting to prevent burrs
Implementation Method 2
an insulating adhesive layer is applied to the backsheet about the opening in which the conductive patch is received, such that the insulating adhesive layer electrically isolates the conductive patch from the metal foil
Data Source
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AI summary
A generally planar, flexible light source assembly or OLED device includes a generally planar, flexible light emitting member having opposite first and second surfaces. An impermeable backsheet is disposed along the first surface of the light emitting surface and includes a conductive portion and an opening O trough the backsheet, A conductive tab or cover is received over the opening, and an insulator is disposed between the tab cover and the opening to mitigate the risk of electrical contact between the components. The insulator can be precut washer-like members or an applied insulating material situated between the conductive components of the light source assembly that pose a potential for shorting. Using tabs with burr-free edges also mitigates against the risk of electrical shorting.