Keyboard Aftertouch Detection Through Curved-Plane Displacement Geometry
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Solution Overview
Problem
Existing keyboard devices face challenges in accurately detecting key-pressing information while maintaining a compact size, as the displacement member's size increase leads to larger devices and higher costs.
Innovation Solution
A keyboard device design featuring a displacement member with a curved surface and plane part on its outer peripheral surface, which rotates to change the penetration amount into a coil's detection region, allowing for accurate detection of key-pressing information while minimizing the displacement member's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the size of the displacement member is increased to increase the difference between sensor output values for accurate key-pressing detection, then the measurement precision is improved, but the device size and cost increase
Solution Approach 1:
The detected part is divided into multiple segments (first detected part and second detected part) with different curvatures. The first detected part has a larger curvature and the second detected part has a smaller curvature, allowing each segment to contribute differently to the sensor output signal. This segmentation enables accurate key-pressing detection without requiring a large overall displacement member size.
Solution Approach 2:
Different parts of the detected part are given different local qualities in terms of curvature. The first detected part has a larger curvature while the second detected part has a smaller curvature. This local quality variation optimizes the sensor output difference for key-pressing detection while maintaining a compact displacement member size.
2Measurement precision
If the size of the displacement member is increased to increase the difference between sensor output values, then the detection accuracy is improved, but the device cost increases
Solution Approach 1:
The detected part is segmented into multiple parts with different curvatures, which creates sufficient sensor output value difference for accurate detection without increasing the overall size. This approach reduces manufacturing costs by avoiding the need for larger, more expensive displacement members while maintaining detection accuracy.
Solution Approach 2:
The curvature parameter of the detected part is varied across different segments. By changing the curvature parameter rather than increasing the overall size, the patent achieves better sensor output differentiation at lower manufacturing cost.
3Measurement precision
If a conventional detected part design is used, then the device structure is simple, but the dynamic range of sensor output values is limited reducing detection accuracy
Solution Approach 1:
The detected part is divided into multiple segments with different curvatures, which expands the dynamic range of sensor output values. This segmentation increases detection accuracy while adding only moderate structural complexity that is justified by the performance improvement.
Solution Approach 2:
The patent uses curved surfaces with different curvatures for the detected part segments. The first detected part has a larger curvature and the second has a smaller curvature, utilizing curvature variation to expand the sensor output dynamic range and improve detection accuracy.
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
The design enables precise detection of key-pressing information, including aftertouch, by expanding the dynamic range of sensor output values without increasing the device's size or cost, and improves the durability and accuracy of key detection.
Implementation Method 1
a coil, facing the detected part and generating a magnetic field
Implementation Method 2
The current (magnetic field) flowing through the coil 57 changes through relative displacement of the metal plate 55 with respect to the coil 57
Data Source
AI summary
Since the curvature of a plane part 82b is smaller than that of a curved surface part 82a, it is possible for the distance between a coil 100 and the detected part 82 (plane part 82b) to be short in the aftertouch performance region than the case where the detected part 82 is one arc shape centered on a rotation shaft 90. Accordingly, the dynamic range can expand (with a significantly decrease in the sensor output value in the aftertouch performance region) without enlarging the displacement member 8 (coil 100). Accordingly, aftertouch can be accurately detected while the displacement member 8 can be miniaturized.