Trapezoidal COF Bonding Pins for Display Panel Alignment
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Solution Overview
Problem
The challenge in bonding a display panel and a chip-on-film (COF) package arises from excessive or insufficient expansion during the bonding process, leading to misalignment and failure of the bonding process due to the increasing precision requirements with higher pixel density and smaller mechanical design.
Innovation Solution
The use of trapezoidal panel and package bonding pins that can shift along their longitudinal direction to align and contact each other, with a wide rear end and narrow front end, allowing for partial overlay to accommodate expansion issues, ensuring proper alignment and bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the COF package is designed with narrower and closer bonding pins to accommodate expansion, then the precision requirement is reduced, but the COF package may still excessively or insufficiently expand during bonding causing misalignment and bonding failure
Solution Approach 1:
The bonding pins are designed with a trapezoidal cross-section featuring a wide rear end and narrow front end, enabling dynamic adjustment during the bonding process. When the COF package expands excessively or insufficiently, the pins can shift longitudinally along their axis while maintaining contact through their tapered geometry, transforming a static alignment constraint into a dynamic compensation mechanism that adapts to expansion variations
Solution Approach 2:
The invention changes the geometric parameters of the bonding pins by采用ing a trapezoidal cross-section instead of a uniform cylindrical shape. This parameter change creates a longitudinal gradient in pin width (wide rear end to narrow front end), which enables the pins to accommodate positional shifts and maintain effective bonding contact despite variations in COF package expansion during the bonding process
2Productivity
If the pixel density of the display panel is increased and the COF package is made smaller, then the screen-to-body ratio is improved, but the number of bonding pins increases and the precision requirement for bonding becomes higher
Solution Approach 1:
The trapezoidal bonding pin design introduces dynamic adjustment capability along the longitudinal axis. The varying width from rear to front allows the pins to shift position and maintain contact during bonding, effectively reducing the impact of high precision requirements that would otherwise be necessary when increasing pixel density and decreasing COF package size
3Reliability
If the COF package expands excessively or insufficiently during bonding, then the bonding process fails due to misalignment, but using traditional cylindrical pins cannot accommodate such expansion variations
Solution Approach 1:
The bonding pins are designed with a trapezoidal cross-section featuring a wide rear end and narrow front end, enabling dynamic adjustment during the bonding process. When the COF package expands excessively or insufficiently, the pins can shift longitudinally along their axis while maintaining contact through their tapered geometry, transforming a static alignment constraint into a dynamic compensation mechanism that adapts to expansion variations
Solution Approach 2:
The invention changes the geometric parameters of the bonding pins by采用ing a trapezoidal cross-section instead of a uniform cylindrical shape. This parameter change creates a longitudinal gradient in pin width (wide rear end to narrow front end), which enables the pins to accommodate positional shifts and maintain effective bonding contact despite variations in COF package expansion during the bonding process
Data Source
AI summary
A display panel and chip-on-film (COF) package bonding structure is provided and includes a display panel including a panel substrate and a plurality of panel bonding pins. The panel bonding pins are disposed on the panel substrate and are arranged along a lateral direction. Each of the panel bonding pins is trapezoidal and is directed along a longitudinal direction. A COF package is bonded to the display panel and includes a package substrate and a plurality of package bonding pins. The package bonding pins are disposed on the package substrate, are arranged along the lateral direction, and are bonded to the panel bonding pins respectively. Each of the package bonding pins is trapezoidal and along the longitudinal direction. The trapezoidal panel bonding pins and package bonding pins can be aligned with and contacts each other.