Capacitive Pen Electrode Layout for Thin Tilt Detection
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Solution Overview
Problem
Existing capacitive electronic pens face challenges in achieving a thin design while maintaining conductivity and accurately detecting inclination angles, leading to potential deformation and waving of the writing trace due to capacitive coupling issues.
Innovation Solution
The electronic pen features a core body with a spherical section and a shaft center section, where the shaft center section is detachably fitted to a core body holder, and a peripheral electrode surrounds the core body excluding the distal end, allowing capacitive coupling with the position sensor to detect inclination angles without thickening the trailing end.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the core body is made thin to achieve a thinner electronic pen design, then the overall pen size is reduced, but the conductivity and structural strength are compromised
Solution Approach 1:
The core body is constructed as a composite structure combining a resin base material with conductive metal particles dispersed throughout. This composite approach allows the core body to maintain thin dimensions while ensuring adequate conductivity through the distributed metal particles, resolving the contradiction between thinness and conductivity reliability
2Length of moving object
If the core body is made thin for a thinner pen design, then the overall pen size is reduced, but the structural strength and resistance to deformation are reduced
Solution Approach 1:
The composite structure of resin matrix with dispersed conductive metal particles provides both mechanical strength and electrical conductivity. The metal particles reinforce the thin resin structure, preventing deformation under writing pressure while maintaining the thin profile necessary for a slender pen design
3Measurement precision
If the trailing end of the core body is made thick to ensure adequate capacitive coupling for inclination detection, then inclination detection accuracy is improved, but the pen cannot be made thin
Solution Approach 1:
The inclination detection function is extracted from the core body and assigned to a separate peripheral electrode that surrounds the core body. This peripheral electrode is specifically positioned to provide adequate capacitive coupling with the position sensor for accurate inclination detection, while the core body itself can remain thin without requiring a thick trailing end
Solution Approach 2:
The electronic pen is segmented into functionally distinct components: the core body for signal transmission and the peripheral electrode for inclination detection. This segmentation allows each component to be optimized independently - the core body can be thin while the peripheral electrode provides sufficient capacitive coupling area for accurate inclination measurement
4Ease of operation
If the core body is made of resin with conductive metal powder to achieve desired writing feel, then writing performance is improved, but the core body is easily deformed under high pressure
Solution Approach 1:
The resin-based core body mixed with conductive metal powder provides both the desired writing feel through the elastomeric properties and sufficient structural strength through the dispersed metal particles. The composite structure prevents excessive deformation under writing pressure while maintaining the tactile feedback characteristic of resin materials
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 enables thinner pens to accurately detect inclination angles and prevent waving of the writing trace, ensuring uniform capacitive coupling and precise position detection.
Implementation Method 1
A capacitive electronic pen uses capacitive coupling to exchange signals with a position sensor of a position detection device
Implementation Method 2
The peripheral electrode is positioned near the one opening of the housing and formed of a conductor disposed so as to surround at least a portion of the core body excluding the distal end
Data Source
AI summary
A capacitive electronic pen includes a housing, a core body, and a peripheral electrode. In the capacitive electronic pen, the core body includes an electrode core formed of a conductor having a spherical section and a shaft center section. The spherical section of the electrode core is not surrounded by the peripheral electrode and is disposed on a tip (distal) end of the capacitive electronic pen protruding from one opening in the axial direction of the housing. The shaft center section of the electrode core has multiple portions that vary in thickness (a cross-section size) including a thin portion, which coupled with the spherical section, and a thick portion. When the core body is fitted to the core body holder, at least a portion of the shaft center section of the electrode core is thinner than the diameter of the spherical section of the electrode core.