Input Device Electrode Segmentation for Proximity Sensing
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Solution Overview
Problem
Existing input devices using electrostatic capacitance for proximity sensing face challenges in achieving high-accuracy sensing due to insufficient resistance values in detection electrodes, especially when the electrodes are short or made of low-resistance, low-cost materials.
Innovation Solution
The input device incorporates first and second detection electrodes with parallel current path portions and connection portions, allowing for adjustable resistance values by varying the spacing between connection portions, enabling high-accuracy proximity sensing even with small current paths and low-cost electrode materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the length of detection electrode is small, then device size is reduced, but resistance value cannot be increased sufficiently
Solution Approach 1:
The detection electrode is divided into multiple segments with connection portions between them. Each segment acts as a separate current path, and the connection portions allow these paths to be combined in parallel, effectively increasing the total resistance value without increasing the overall electrode length.
Solution Approach 2:
Instead of increasing resistance by extending the electrode length in one dimension, the invention introduces multiple current paths in the vertical dimension through connection portions. This transforms the resistance enhancement from a one-dimensional length problem to a multi-dimensional current path distribution problem.
2Ease of manufacture
If low-resistance, low-cost electrode film is used, then manufacturing cost is reduced, but sufficient resistance value cannot be obtained
Solution Approach 1:
The electrode film is segmented into multiple sections with connection portions, creating multiple current paths. This allows the use of low-resistance materials while achieving sufficient total resistance through the parallel combination of multiple paths, maintaining both cost-effectiveness and performance.
Solution Approach 2:
The invention changes the electrical parameters of the electrode system by introducing multiple current paths with different resistance characteristics. By adjusting the number and configuration of connection portions, the total resistance can be optimized while using low-cost electrode materials.
3Volume of moving object
If current path length is small, then electrode size is reduced, but electrostatic capacitance value shows almost no change even when operating body is in close proximity
Solution Approach 1:
The detection electrode is segmented into multiple sections that each contribute to the overall electrostatic capacitance measurement. This segmentation allows for better detection sensitivity by distributing the sensing function across multiple sections while maintaining a compact overall size.
Solution Approach 2:
The invention enhances proximity sensing capability by introducing vertical current paths through connection portions. This multi-dimensional current path structure increases the effective sensing area and improves capacitance change detection sensitivity without increasing the horizontal electrode footprint.
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 configuration allows for easy adjustment of resistance values, enhancing the accuracy of proximity sensing and reducing costs by using low-cost materials while maintaining detection sensitivity.
Implementation Method 1
an input device that performs proximity sensing on an operating body relative to an operation surface on the basis of electrostatic capacitance values of detection electrodes
Implementation Method 2
each of the first detection surfaces has one or more second current path portions and a pair of first connection portions via which the one or more second current path portions and the first current path portion are connected in parallel to each other
Data Source
AI summary
An input device includes: an operation surface that receives an operation from an operating body that is in close proximity thereto; and first detection electrodes that are arranged along the operation surface and that extend parallel to each other in a first direction. Each of the first detection electrodes has first detection surfaces that are provided side by side in the first direction and a first current path portion that extends linearly in the first direction and via which the first detection surfaces are connected to each other; and each of the first detection surfaces has one or more second current path portions and a pair of first connection portions via which the one or more second current path portions and the first current path portion are connected in parallel to each other.