Display Device Non-Linear Sensing Pads Reduce PCB Overlap
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Solution Overview
Problem
The attachment of printed circuit boards (PCBs) for input sensing units to display panels can lead to manufacturing problems and defects due to overlapping positions, causing complexity and defects in the display device manufacturing process.
Innovation Solution
A display device design that reduces the width of the pad connection part of the input sensing unit and correspondsingly the Chip On Flexible Printed Circuit (COF), minimizing overlap and defects by using a non-linear configuration of sensing pads and signal lines, and anisotropic conductive films for electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If PCBs for input sensing unit and display are disposed in close overlapping positions, then device integration is improved, but manufacturing defects increase due to heat attachment problems
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement of PCBs to a three-dimensional stacked configuration where the input sensing unit PCB is positioned above the display PCB. This vertical stacking enables closer integration while preventing manufacturing defects by eliminating direct overlapping in the same plane during heat attachment processes.
Solution Approach 2:
The patent implements a nested structure where the input sensing unit PCB is effectively nested above the display PCB, with both boards vertically aligned but separated by adhesive layers. This nesting approach achieves high device integration while maintaining manufacturing precision by preventing direct contact and heat transfer issues between overlapping PCBs.
2Manufacturing precision
If width of pad connection part is reduced, then overlap and manufacturing defects are minimized, but electrical connectivity requirements become more challenging
Solution Approach 1:
The patent employs flexible COF (Chip On Flexible) circuits as thin film structures to achieve electrical connectivity with reduced pad widths. The flexible nature of these thin film connections allows for miniaturized pad designs while maintaining reliable electrical pathways, thus minimizing overlap issues without compromising connectivity reliability.
Solution Approach 2:
The patent changes the physical parameters of the connection structure by transitioning from rigid wide pads to flexible thin-film connections with optimized width and thickness parameters. This parameter optimization enables reduced pad widths while maintaining electrical reliability through controlled impedance and conductive material properties.
3Manufacturing precision
If non-linear configuration of sensing pads is used, then manufacturing stability is enhanced, but layout design complexity increases
Solution Approach 1:
The patent implements asymmetric and non-linear arrangements of sensing pads and signal lines that optimize manufacturing stability. By departing from symmetric linear patterns, the design accommodates manufacturing tolerances and reduces sensitivity to alignment variations, enhancing manufacturing stability despite increased layout design complexity.
Solution Approach 2:
The patent applies local quality optimization by varying the configuration of sensing pads and signal lines in different regions of the PCB. This localized optimization allows tailored arrangements that enhance manufacturing stability in critical areas while managing overall layout complexity through region-specific design strategies.
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 design enhances manufacturing stability by reducing overlap and defects, allowing for more efficient and accurate attachment of PCBs, thereby improving the manufacturing process and reducing errors.
Implementation Method 1
a plurality of sensing pads disposed on the anisotropic conductive film and electrically connected to the second printed circuit board by the anisotropic conductive film
Implementation Method 2
a first adhesive member disposed on the display area of the display panel and a portion of the first printed circuit board
Data Source
AI summary
A display device includes: a display panel having a single display area including a plurality of light emitting elements and a single non-display area having a plurality of display pads electrically connected to the plurality of light emitting elements; a first printed circuit board disposed on the single non-display area of the display panel and electrically connected to the plurality of display pads; a first adhesive member disposed on the single display area of the display panel and a portion of the first printed circuit board; a second printed circuit board overlapping with the single non-display area; an anisotropic conductive film disposed on the second printed circuit board; a plurality of sensing electrodes overlapping with the single display area; a plurality of signal lines, each of which is connected to a corresponding one of the plurality of sensing electrodes; and a plurality of sensing pads disposed on the anisotropic conductive film and electrically connected to the second printed circuit board by the anisotropic conductive film. The sensing pads are arranged in a plurality of rows in a plan view and overlap with the single non-display area; and a base film disposed on the plurality of sensing electrodes, the plurality of signal lines, and the plurality of sensing pads.