Active Stylus Core Geometry for Efficient Wireless Charging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional active styluses for capacitive touch sensors lack efficient wireless charging due to suboptimal coupling factors between charging coils, limiting charging efficiency and requiring alignment aids for proper alignment.
Innovation Solution
Incorporating a core with specific shapes, such as the Tu (±) core, into the active stylus to enhance the magnetic flux penetration and coupling factor, thereby improving wireless charging efficiency without the need for wired recharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wireless charging is implemented in active stylus, then charging convenience is improved, but charging efficiency deteriorates due to suboptimal coupling factors
Solution Approach 1:
A ferromagnetic core is introduced as an intermediary component between the transmit coil and receive coil to mediate the magnetic field interaction. The core concentrates and guides magnetic flux, improving the coupling factor between coils and thereby enhancing wireless charging efficiency while maintaining the convenience of wireless charging operation.
Solution Approach 2:
The magnetic properties of the charging system are changed by introducing a ferromagnetic core with high permeability. This parameter change concentrates magnetic flux and increases the coupling factor between transmit and receive coils, directly improving charging efficiency without compromising the wireless charging convenience.
2Loss of energy
If ferromagnetic core is added to improve coupling factor, then charging efficiency is improved, but device complexity increases
Solution Approach 1:
The ferromagnetic core is integrated with the receive coil assembly, merging multiple functions into a single component structure. This reduces the overall number of separate parts and simplifies the stylus structure while maintaining the improved charging efficiency that the core provides.
Solution Approach 2:
The ferromagnetic core serves multiple functions: it concentrates magnetic flux to improve coupling factor, provides structural support for the coil assembly, and may serve as a mounting surface for other components. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
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 use of core shapes like the Tu core increases the magnetic flux penetration, enhancing the coupling factor and thus improving the efficiency of wireless charging, reducing recharge times and eliminating the need for wired connections.
Implementation Method 1
a wireless charging receive coil configured to transduce flux of a magnetic field generated by the wireless charging transmit coil into electrical current
Implementation Method 2
an active stylus may include a core configured to increase an amount of flux that penetrates the receive coil
Data Source
AI summary
An example active stylus includes a core comprising: a main cylinder having a first end, a second end; a first supplemental cylinder disposed at the first end of the main cylinder and having a diameter that is larger than a diameter of the main cylinder; a second supplemental cylinder disposed between the first supplemental cylinder and the second end of the main cylinder and having a diameter that is larger than the diameter of the main cylinder; and a wireless charging receive coil configured to transduce flux of a magnetic field generated by a wireless charging transmit coil into electrical current, wherein the wireless charging receive coil is positioned around a longitudinal axis of the main cylinder of the core and between the first supplemental cylinder and the second supplemental cylinder.