Touch Panel Junction Structure with Insulating Spacer Columns
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Solution Overview
Problem
The bonding process between touch panels and flexible printed circuit boards often results in deformations and weak bonding strength due to the thickness of the adhesive layer becoming thin under the insulating and protective layers, leading to performance degradation and structural instability.
Innovation Solution
A touch panel design featuring an adhesive layer, a protective layer, a touch sensor portion, and bonding pads with a first insulating layer extending between the pads to maintain uniform thickness and enhance bonding stability, using anisotropic conductive films or materials for secure attachment to the flexible printed circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the bonding process is performed with pressing means on the bonding pad portion, then the bonding strength between touch panel and flexible printed circuit board is improved, but the adhesive layer thickness becomes non-uniform and elements deform
Solution Approach 1:
The bonding pad portion is divided into multiple unit bonding pads arranged in an array, with insulating columns positioned between them. This segmentation allows the pressing force to be distributed across multiple discrete bonding points rather than concentrating stress on a single large pad, preventing adhesive layer thinning and element deformation while maintaining adequate bonding strength.
Solution Approach 2:
Insulating columns are introduced as intermediary structures between adjacent unit bonding pads. These columns serve as spacers that maintain the thickness of the adhesive layer and prevent direct contact between conductive elements during the bonding process, thereby preventing deformation while allowing bonding to proceed.
2Reliability
If insulating layer and protective layer are formed with considerable thickness for protection, then element protection is improved, but adhesive layer thickness becomes non-uniform under the bonding area
Solution Approach 1:
The insulating structure is designed with local quality variation: insulating columns are positioned specifically in the bonding pad area where thickness control is critical, while the protective layer maintains considerable thickness in non-bonding areas for element protection. This localized approach allows protection without compromising adhesive layer uniformity in the bonding region.
Solution Approach 2:
The insulating columns extend in the vertical dimension (thickness direction) to provide spacing, while the protective layer provides horizontal coverage. This multi-dimensional approach allows the protective function to be separated from the thickness control function, enabling both element protection and uniform adhesive layer thickness.
3Area of stationary object
If unit bonding pads are arranged closely for compact design, then device area is reduced, but adhesive layer thickness becomes non-uniform during bonding
Solution Approach 1:
Insulating columns are placed between closely arranged unit bonding pads to act as spacers. These intermediary structures maintain the adhesive layer thickness even when bonding pads are positioned close together, enabling compact design without sacrificing manufacturing precision.
Solution Approach 2:
The bonding pad area is segmented into multiple small unit bonding pads with insulating columns between them, rather than using a single large pad. This segmentation allows closer spacing while maintaining uniform adhesive layer thickness through the spacer columns.
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
Prevents deformations and maintains the structural stability of the junction structure by ensuring uniform adhesive layer thickness, thereby securing the bonding strength and preventing performance degradation.
Implementation Method 1
bonded to a flexible printed circuit board with an anisotropic conductive film (ACP) as an intermediate
Data Source
AI summary
A touch panel includes: an adhesive layer formed on a base film; a protective layer formed on the adhesive layer; a touch sensor portion formed on the protective layer; a bonding pad portion comprising a plurality of unit bonding pads formed on the protective layer as electrically connected to the touch sensor portion; and a first insulating layer formed on the protective layer to extend from a unit bonding pad while filling separation regions between the unit bonding pads. Since the deformations in the elements of the touch panel during the process of bonding the touch panel and the flexible printed circuit board are prevented, there are effects that the degradation in the performance of the touch panel is prevented, and the structural stability of the junction structure of the touch panel and the flexible printed circuit board is secured.