Low Temperature Solder for Flexible OLED Electrical Connections
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Solution Overview
Problem
Existing methods for establishing electrical connections in organic light emitting diode (OLED) devices face challenges due to the flexible and temperature-sensitive nature of these devices, leading to issues with reliability, durability, and processing time, particularly with materials like silver epoxy and double-sided conductive tape which suffer from delamination and poor electrical properties at lower temperatures.
Innovation Solution
A lighting assembly and method using a low temperature solder material with compatible patch materials like silver, copper, or tin, applied through a flat flex cable with conductive pads and patches on a backsheet, ensuring hermetic sealing and flexible electrical connections, allowing for efficient and reliable connections at temperatures below 200°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If higher temperatures are used for processing connection materials, then acceptable connection is achieved, but OLED temperature limits are exceeded causing damage
Solution Approach 1:
The patent changes the melting point parameter of the solder material to below 200°C (preferably below 150°C), enabling the soldering process to occur at temperatures compatible with OLED limitations. This parameter change allows achieving acceptable connection quality while maintaining processing temperatures below the OLED's maximum tolerance, preventing thermal damage to the organic layers.
Solution Approach 2:
The low melting point solder acts as an intermediary material that bridges the electrical connection between the rigid backsheet and the flexible OLED while withstanding the mechanical and thermal stresses. The solder's low melting point enables it to be processed at temperatures the OLED can tolerate, while its metallurgical bonding properties ensure connection reliability without requiring higher temperatures that would damage the device.
2Temperature
If lower temperatures are used for processing, then OLED damage is avoided, but processing time increases to more than 4 hours
Solution Approach 1:
The patent changes the melting point parameter of the solder material to below 200°C (preferably below 150°C), which enables the soldering process to proceed rapidly at low temperatures. The low melting point allows the solder to become sufficiently fluid and adhesive quickly, achieving reliable connections in minutes rather than hours, thus reducing processing time while maintaining temperature compatibility with OLEDs.
Solution Approach 2:
The patent utilizes the phase transition (melting) of low melting point solder materials at temperatures below 200°C to achieve rapid bonding. The phase change from solid to liquid state occurs quickly at these low temperatures, enabling fast wetting and adhesion to the contact surfaces, thereby reducing the time required to establish reliable electrical connections without exposing the OLED to damaging temperatures.
3Strength
If conventional soldering materials are used, then strong connection is achieved, but flexibility and ductility are compromised
Solution Approach 1:
The patent changes the melting point parameter of the solder material to below 200°C, which fundamentally alters the solder's mechanical properties. Low melting point solders exhibit greater ductility and flexibility at room temperature compared to conventional high-temperature solder materials. This parameter change enables the solder to accommodate the flexibility and bending of the OLED device while maintaining strong adhesion and reliable electrical connections, thus preserving both connection strength and device flexibility.
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
The solution provides a durable, flexible, and efficient electrical pathway for OLED devices, maintaining hermeticity and flexibility while reducing processing time and improving adhesion, thus enhancing the longevity and performance of the OLED panel connections.
Implementation Method 1
A low temperature solder material is disposed between each connector pad and contact patch for establishing electrical connection with the light source
Implementation Method 2
improving adhesion, thus enhancing the longevity and performance of the OLED panel connections
Data Source
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AI summary
A lighting assembly (100) includes a light source (102) having a first generally planar, light source including a perimeter edge. A back- sheet (110) is disposed in substantially parallel relation with the light source, and includes at least one electrical feedthrough region (120) extending through the backsheet and substantially covered by a contact patch (106) disposed in substantially planar relation between the backsheet and the light source. A generally planar, connector cable (122) extends over the backsheet and has connector pad(s) positioned thereon to associate with each feedthrough and to the light source through the contact patch. A low temperature solder material (160) is disposed between each connector pad and contact patch for establishing electrical connection with the light source, wherein one or more of the light source, connector cable, backsheet, or any portion thereof is constructed of one or more plastics.