Touch Panel Adhesive Insulating Layer Segmentation
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Solution Overview
Problem
The existing touch panel technologies face difficulties in forming a bonding pad without a separate patterning process, as the adhesive insulating layer covers the bonding pads, leading to a step difference due to its thickness and increased process time and cost.
Innovation Solution
A touch panel design where the adhesive insulating layer is selectively formed on regions except for the bonding pads, allowing exposure without requiring a separate patterning process, using a combination of first and second adhesive insulating layers with varying areas to cover the sensing electrode pattern layers and wires while leaving the bonding pads uncovered.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating material layer is coated on the entire surface of the sensing electrode pattern layers to insulate them, then insulation between layers is achieved, but the bonding pad cannot be exposed and step difference occurs due to the thickness of the insulating material
Solution Approach 1:
The insulating material layer is segmented into multiple layers: a first insulating material layer that covers the bonding pad region (allowing wire exposure) and a second insulating material layer that covers the sensing electrode pattern layers (providing insulation). This segmentation allows different regions to have different insulation characteristics, solving both the insulation requirement and the bonding pad exposure requirement.
Solution Approach 2:
Different regions of the touch panel have different insulating properties. The bonding pad region has no insulating material (or has a different insulating structure) to allow wire connection, while the sensing electrode pattern layers have insulating material for electrical insulation. This local differentiation of insulating quality resolves the contradiction between needing insulation and needing exposed bonding pads.
2Reliability
If an insulating material layer is coated on the entire surface of the sensing electrode pattern layers, then insulation is achieved, but a separate patterning process is required to expose the bonding pad, increasing process time and cost
Solution Approach 1:
The insulating material layers are formed with predetermined patterns during the initial coating process, rather than applying a complete insulating layer and then removing material through patterning. The first insulating material layer is formed to expose the bonding pad region, and the second insulating material layer is formed to cover the sensing electrode pattern layers. This preliminary formation of the insulating structure eliminates the need for subsequent patterning processes to expose the bonding pad.
3Reliability
If the insulating material layer thickness is greater than the wire thickness, then insulation is sufficient, but step difference occurs in the wire of each sensing electrode pattern layer
Solution Approach 1:
The insulating material is segmented into two layers with different thickness distributions. The first insulating material layer is thinner or absent at the bonding pad region to match the wire height, eliminating step difference. The second insulating material layer provides additional insulation where needed. This layered segmentation allows the insulating structure to adapt to different regional requirements, maintaining both sufficient insulation and flat wire surfaces.
Data Source
AI summary
Disclosed is a touch panel. The touch panel includes a sensing electrode pattern layer on a transparent substrate; a wire connected to the sensing electrode pattern layer; a bonding pad formed at an end of the wire and connected to a flexible printed circuit board (FPCB); and an adhesive insulating layer on one surface of the sensing electrode pattern layer and on a region except for the bonding pad, wherein the adhesive insulating layer comprises a first adhesive insulating layer and a second adhesive insulating layer, and an area of the first adhesive insulating layer is different from an area of the second adhesive insulating layer.