Fine Pad Lines for OLED Display Adhesion
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Solution Overview
Problem
In organic light-emitting display devices, insufficient adhesion between pads, circuit boards, and conductive films leads to increased contact resistance, which degrades over time due to heat and residual stress, limiting the device's performance and reliability.
Innovation Solution
A display device design featuring a substrate with fine pad lines patterned in specific orientations, such as zigzag or mesh patterns, and an insulating resin dispersed between these lines to enhance adhesion, using an anisotropic conductive film with conductive particles for electrical connection, thereby improving the contact reliability between pads and circuit terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat and pressure are applied to the conductive film to electrically connect the pad and the circuit board, then electrical connection is achieved, but adhesion decreases over time due to heat generated during driving and residual stress
Solution Approach 1:
The pad is divided into multiple fine pad lines instead of being a single continuous structure. This segmentation allows the insulating resin to be dispersed into regions between the fine pad lines during thermal compressing, creating a more robust connection structure that resists degradation over time from heat and stress.
2Reliability
If a conductive film is interposed between the pad and the circuit board, then electrical connection is established, but contact resistance increases when adhesion is not satisfactory
Solution Approach 1:
The pad is segmented into fine pad lines that increase the total contact area with the conductive film. This segmentation, combined with the dispersion of insulating resin into the regions between fine pad lines, ensures satisfactory adhesion and maintains low contact resistance.
Solution Approach 2:
The insulating resin is selectively dispersed into specific regions between the fine pad lines during thermal compressing, creating localized areas of enhanced adhesion and electrical contact while maintaining insulation where needed.
3Reliability
If the pad is designed with a specific pattern of fine pad lines, then adhesion is enhanced, but device complexity increases
Solution Approach 1:
The pad is segmented into fine pad lines arranged in systematic patterns (such as mesh or parallel arrangements). While this increases structural complexity, the regularity of the patterns allows for efficient manufacturing and maintains overall device simplicity.
Solution Approach 2:
The pad structure is modified by changing the pattern parameters (line width, spacing, arrangement) to optimize adhesion. These parameter changes are made in a controlled manner that enhances reliability without excessively complicating the device design.
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 enhanced adhesion and conductivity reduce contact resistance, allowing for increased current flow without electrical short-circuits, improving the reliability and performance of organic light-emitting display devices, even under high current conditions.
Implementation Method 1
a conductive film between the substrate and the circuit board and including a plurality of conductive particles for electrically connecting the first pad and the circuit terminal
Implementation Method 2
a region into which the insulating resin is dispersed during a thermal compressing operation located between adjacent ones of the fine pad lines
Data Source
AI summary
A display device includes a substrate comprising a display unit for displaying an image, a non-display unit around the display unit, and at least one first pad for sending an electrical signal to the display unit, a circuit board on the substrate and comprising at least one circuit terminal, and a conductive film between the substrate and the circuit board and including a plurality of conductive particles for electrically connecting the first pad and the circuit terminal, and an insulating resin surrounding the conductive particles, wherein the first pad includes a plurality of fine pad lines, and a region into which the insulating resin is dispersed during a thermal compressing operation located between adjacent ones of the fine pad lines.