Single-Layer Touch Sensor Layout for Lower-Cost Multi-Touch Displays
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Solution Overview
Problem
The high cost of manufacturing touch sensor panels with drive and sense lines on both sides of a substrate is due to the need for protective measures and flex circuit fabrication and bonding on both sides, making them expensive to produce.
Innovation Solution
The solution involves fabricating drive and sense lines on a co-planar single layer on one side of the substrate, with column-like patterns and patches connected by metal traces in the border area, allowing a small flex circuit to be bonded to one side, eliminating the need for dual-sided processing and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If drive and sense lines are formed on both sides of the substrate, then touch sensitivity and accuracy are improved, but manufacturing cost increases due to protective measures and flex circuit fabrication on both sides
Solution Approach 1:
The patent transitions from a dual-sided substrate architecture to a single-sided substrate architecture by moving all drive and sense lines to one side. This dimensional reorganization eliminates the need for backside processing, protective measures, and dual-sided flex circuits, thereby reducing manufacturing cost while preserving touch detection functionality through the use of transparent conductive materials that maintain optical and electrical performance.
Solution Approach 2:
The patent combines both drive lines and sense lines onto a single side of the substrate, merging functions that were previously separated across two sides. This consolidation eliminates redundant manufacturing steps, reduces the number of flex circuits needed, and simplifies the overall structure while maintaining the mutual capacitance sensing mechanism required for accurate touch detection.
2Adaptability or versatility
If drive and sense lines are formed on both sides of the substrate, then touch detection capability is improved, but device complexity increases due to dual-sided processing and flex circuit bonding
Solution Approach 1:
The patent extracts the sense lines from the backside of the substrate and relocates them to the front side, where they can share the same plane as the drive lines. This extraction eliminates the need for separate backside processing equipment, reduces the complexity of aligning and bonding flex circuits to both sides, and simplifies the manufacturing workflow while preserving all touch detection capabilities.
3Manufacturing precision
If thin-film processing steps are performed on both sides of the glass substrate, then transparent conductive lines can be formed, but manufacturing time and cost increase due to protective measures required
Solution Approach 1:
The patent performs all thin-film deposition and patterning operations on the front side of the substrate before any assembly or protective coating steps. By completing all critical conductive line formation operations in advance on a single side, the manufacturing process eliminates the need for intermediate protective measures that would otherwise be required between backside processing steps, thereby reducing total manufacturing time and process complexity.
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 approach results in a cost-effective, transparent touch sensor panel capable of detecting single or multi-touch events with improved manufacturability and reduced production costs, while maintaining touch sensitivity and accuracy.
Implementation Method 1
a mutual-capacitance multi-touch sensor panel capable of being fabricated on a single side of a substrate
Data Source
AI summary
A touch sensor panel having co-planar single-layer touch sensors fabricated on a single side of a substrate is disclosed. The drive and sense lines can be fabricated as column-like patterns in a first orientation and patches in a second orientation, where each column-like pattern in the first orientation is connected to a separate metal trace in the border area of the touch sensor panel, and all patches in each of multiple rows in the second orientation are connected together using a separate metal trace in the border area of the touch sensor panel. The metal traces in the border areas can be formed on the same side of the substrate as the patches and columns, but separated from the patches and column-like patterns by a dielectric layer.