Integrated Touch Sensor Shielding for Thin Secondary Sensor Stackups
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Solution Overview
Problem
Existing touch sensor technologies face challenges in reducing the overall thickness of the sensor stackup and minimizing noise interference, particularly when incorporating secondary sensors, which can compromise touch sensitivity and increase device thickness.
Innovation Solution
Incorporating a secondary sensor as part of the touch sensor pattern and grounding or AC coupling it to maintain a steady state during touch scan cycles, allowing for reduced thickness and effective shielding to prevent noise interference, thereby ensuring touch sensitivity across the entire surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a secondary sensor is incorporated into the touch sensor pattern, then the sensor can provide additional functionality (e.g., button press detection), but the overall thickness of the sensor stackup increases
Solution Approach 1:
The secondary sensor is merged with the touch sensor pattern by forming both sensors using the same conductive material layers and processing steps. The secondary sensor pattern is integrated into the existing touch sensor electrode structure, allowing both sensors to share common manufacturing processes and material layers, thereby reducing overall thickness while maintaining dual functionality.
Solution Approach 2:
The conductive material layers are designed to serve multiple functions: they form both the touch sensor electrodes and the secondary sensor electrodes. This multi-functionality allows a single layer structure to provide both touch sensing capability and secondary sensor functionality, eliminating the need for separate dedicated layers for each sensor type.
2Adaptability or versatility
If a secondary sensor is incorporated into the touch sensor pattern, then additional functionality is achieved, but noise interference increases and touch sensitivity is compromised
Solution Approach 1:
The sensor structure is segmented into distinct functional regions: the touch sensor pattern area and the secondary sensor area. By spatially separating these functions within the same layer structure, the patent reduces electromagnetic interference between the two sensor types while maintaining their individual performance characteristics.
Solution Approach 2:
The conductive material layers serve as an intermediary structure that enables both sensor types to coexist. The specific configuration of these layers acts as a mediator that minimizes noise coupling between the touch sensor and secondary sensor, allowing both to function simultaneously without significant interference.
3Object-affected harmful factors
If the secondary sensor is grounded or held at steady state during touch scan cycles, then shielding against noise is achieved, but the complexity of sensor control increases
Solution Approach 1:
The secondary sensor is held at a steady state or grounded during specific phases of the touch scan cycle. This periodic control strategy synchronizes the secondary sensor state with the touch sensing operations, providing noise shielding during critical measurement periods while maintaining simplicity through regular, predictable control patterns.
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 significantly reduces the sensor stackup thickness, allowing for more space in devices like batteries, while maintaining touch sensitivity and shielding against noise interference, ensuring reliable touch functionality.
Implementation Method 1
grounding the secondary sensor can shield the touch sensor pattern at the area of the touch sensor pattern where the secondary sensor is formed
Implementation Method 2
the secondary sensor can be held at a steady state by AC coupling the secondary sensor to at least one of a DC voltage or ground
Implementation Method 3
Touch screens can recognize a touch event and the position of the touch event on the touch sensor panel
Data Source
AI summary
A touch sensor pattern with a secondary sensor formed substantially as part of the touch sensor pattern is provided. By forming the secondary sensor substantially as part of the touch sensor pattern, where the secondary sensor can be held at a steady state or ground during a touch scan cycle of the touch sensor, an overall thickness of the stackup at the area of the touch sensor where the secondary sensor is formed can be significantly reduced. The reduction in the thickness can allow more space for other hardware such as a device battery, for example. Moreover, grounding the secondary sensor can shield the touch sensor pattern at the area of the touch sensor pattern where the secondary sensor is formed, during a touch scan cycle.