Capacitive Touch Sensor with Non-Conductive Cover Window
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Solution Overview
Problem
Conventional 3-D capacitive touch sensors require multiple layers with conductive materials, leading to manufacturing complexities, increased costs, and reduced yield due to the need for Indium Thin Oxide (ITO) on cover windows, which complicates the production of 2.5-D glass and GORILLA glass shapes.
Innovation Solution
A two-layer capacitive touch sensor design where the top layer has capacitive sensors arranged in a ring-shaped pattern with minimal routing outside the active area, eliminating the need for a top guard layer with conductive material, and utilizing the display's conductive material as a bottom guard for the second layer, allowing for a non-ITO cover window and reduced substrate layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional 3-D capacitive touch sensors use multiple layers with conductive materials including ITO on cover windows, then touch sensing capability is achieved, but manufacturing complexity increases and production yield decreases
Solution Approach 1:
The patent extracts and eliminates the ITO conductive layer from the cover window, removing the source of manufacturing complexity while preserving touch sensing functionality through the modified sensor layer configuration
Solution Approach 2:
The patent segments the sensor into distinct functional layers with the top sensor layer patterned to provide both sensing and guarding functions, separating the guard function from the cover window material itself
2Reliability
If ITO is used on cover windows for capacitive touch sensors, then electrical guard function is provided, but production of 2.5-D glass and GORILLA glass shapes becomes more difficult
Solution Approach 1:
The ITO layer is extracted from the cover window structure entirely, eliminating the conflict between conductive material requirements and glass forming processes for 2.5-D shapes
Solution Approach 2:
The top sensor layer itself provides the electrical guard function through its positioning and configuration, eliminating the need for separate ITO guard layers on the cover window
3Reliability
If multiple substrate layers with conductive materials are used, then comprehensive guard and sensing functions are achieved, but the touch sensor becomes thicker and more costly
Solution Approach 1:
The patent merges the guard function and sensing function into the same top sensor layer through strategic positioning, eliminating the need for separate guard layers and reducing overall thickness
Solution Approach 2:
The top sensor layer serves multiple functions simultaneously - it provides touch sensing capability and electrical guarding for the bottom sensor layer, reducing the number of required layers
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 results in a more compact, cost-effective, and thinner touch sensor with reduced manufacturing challenges, enabling the use of normal glass as the cover window and simplifying the production of 2.5-D shapes, while maintaining effective touch sensing capabilities.
Implementation Method 1
capacitive sensors arranged in a first layer and a second layer
Data Source
AI summary
An apparatus including capacitive sensors, where the capacitive sensors are arrange in a first layer and a second layer, and where the first layer is located on top of the second layer; and a cover window on top of the first layer, where the cover window does not comprise electrically conductive material.