Electromagnetic Pointer With Metal Rod Triggering Ferrite Core Resonance
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Solution Overview
Problem
Conventional electromagnetic pointers for e-books/green books face challenges in reducing size while maintaining functionality due to the limitations of ferrite core size and insufficient strength of plastic components, making it difficult to accommodate them within the limited thickness of these devices.
Innovation Solution
An electromagnetic pointer with a joint movable mechanism using a metal rod that penetrates through a ferrite core, triggering a switch device to change the signal emitted, allowing for a reduced diameter of less than 6 mm by varying the inductance or capacitance of the resonance circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional pointer configuration with ferrite core and plastic components is used, then electromagnetic transmission function is maintained, but pointer diameter cannot be reduced below 6 mm
Solution Approach 1:
The patent replaces conventional plastic components with metal components (metal rod, metal plate, metal shell) to create a composite structure that maintains sufficient mechanical strength while enabling miniaturization. The metal materials provide the necessary strength for components smaller than 6 mm in diameter, resolving the contradiction between size reduction and strength maintenance.
Solution Approach 2:
The patent changes the material parameters from plastic to metal, fundamentally altering the mechanical properties of the pointer components. This parameter change enables the pointer to achieve both reduced diameter (below 6 mm) and maintained or enhanced strength, as metal materials have superior strength-to-size ratios compared to plastic.
2Volume of moving object
If ferrite core size is reduced to accommodate pointer in thin e-books, then pointer can fit within device thickness, but electromagnetic transmission efficiency deteriorates
Solution Approach 1:
The patent introduces a metal plate positioned near the ferrite core to form a coupled resonance circuit. This composite structure (ferrite core + metal plate) enhances the electromagnetic transmission efficiency even when the ferrite core is miniaturized, as the metal plate compensates for the reduced core size by providing additional electromagnetic coupling capability.
Solution Approach 2:
The metal plate serves multiple functions: it acts as both a structural component and an electromagnetic coupling element. By integrating this additional functionality into the pointer, the system maintains reliable electromagnetic transmission with miniaturized ferrite core, as the metal plate compensates for the core's reduced dimensions.
3Volume of moving object
If pointer diameter is reduced for accommodation, then device thickness requirement is met, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes from plastic to metal materials, which fundamentally alters the manufacturing characteristics. Metal components can be manufactured with high precision using established metallurgical processes, enabling the production of pointer components smaller than 6 mm in diameter with the required dimensional accuracy and mechanical strength.
Solution Approach 2:
The use of metal materials provides superior dimensional stability and mechanical properties that facilitate precise manufacturing. The composite structure with metal rod, metal plate, and metal shell allows for tight tolerances to be maintained even in miniaturized components, as metal materials resist deformation and maintain geometric integrity better than plastic at small scales.
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
Enables the creation of a compact electromagnetic pointer that can effectively resonate with antennas and sensor coils, overcoming size and material strength limitations, thus suitable for use in e-books and digital tablets.
Implementation Method 1
The inductor constituted by a ferrite core winded with a metal coil and the capacitor constitute the circuit to transmit and receive electromagnetic waves with the antennas or sensor coils
Implementation Method 2
The metal rod penetrates trough the ferrite core and is moveable through the ferrite core. The metal rod triggers the trigger device to change electric properties of the resonance circuit
Data Source
AI summary
An electromagnetic pointer is disclosed. The electromagnetic pointer comprises a pen holder assembly, a circuit board, a metal rod, a ferrite core with coils and a trigger device. The diameter of the pen holder assembly is less than 6 mm. The circuit board comprises a resonance circuit. The metal rod has a low permeability. The ferrite core with coil constitutes an inductor and the coil electrically connects to the circuit board through a conductive wire to complete the resonance circuit. The ferrite core has a hollow center so that the metal rod can move through to trigger the trigger device and change electric properties of the resonance circuit.