Electronic Pen Resonant Circuit Capacitance Switching for Frequency Tuning
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Solution Overview
Problem
The existing electronic pens face challenges in adjusting the reference resonant frequency of their resonant circuits to a standard value due to manufacturing errors, particularly in reducing the size of the substrate, as they require a large area for capacitor adjustment and laser cutting, which is impractical for smaller designs.
Innovation Solution
The integration of a control circuit with capacitor arrays and switches allows for the adjustment of resonant frequencies by changing the capacitance of capacitors, enabling precise tuning of the resonant circuits without the need for extensive wiring or laser cutting, thus allowing for a smaller form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser cutting is used to disconnect capacitors for frequency adjustment, then the reference resonant frequency can be adjusted to a standard value, but the wiring region requires a relatively large area
Solution Approach 1:
The patent merges the capacitor adjustment function with the existing resonant circuit components by integrating multiple capacitors in parallel configuration within the same wiring region, eliminating the need for separate adjustment areas. The control circuit selectively connects or disconnects capacitors through switching elements, combining frequency adjustment functionality with the original circuit layout.
Solution Approach 2:
The patent implements dynamic capacitor selection through control circuits that can selectively connect or disconnect capacitors based on measured resonant frequency values. This dynamic adjustment allows the system to adapt the capacitance value after assembly, achieving precise frequency tuning without requiring large static wiring regions for multiple discrete capacitor options.
2Manufacturing precision
If multiple capacitors are disposed in parallel for frequency adjustment, then the reference resonant frequency can be tuned, but the substrate size increases
Solution Approach 1:
The patent nests multiple capacitors in parallel within the existing circuit architecture, where adjustment capacitors are integrated into the same substrate area as the main resonant circuit components. The control circuit and switching elements are nested within the existing wiring region, allowing frequency adjustment functionality to be embedded without increasing overall substrate footprint.
3Measurement precision
If laser cutting is performed to adjust capacitance, then the resonant frequency accuracy is improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent implements a self-service adjustment mechanism where the control circuit automatically measures the resonant frequency and selectively activates capacitors based on the measured value. This automated feedback loop eliminates the need for manual laser cutting operations and complex post-assembly adjustments, reducing manufacturing process complexity while maintaining frequency 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
This solution enables the electronic pen to adjust its resonant frequencies effectively using a smaller area, ensuring accurate communication and reducing the size constraints of the substrate, while maintaining the ability to transmit pen pressure and switch information reliably.
Implementation Method 1
The coil is excited by a magnetic field that is transmitted from a sensor coil in a position detection device. When the resonant circuit enters a magnetic field, an induced electromotive force is generated on the coil so that electric power is stored in the resonant circuit.
Implementation Method 2
Another method is to change the resonant frequency of the resonant circuit in accordance with the contents of the pen information and transmit the displacement of the resonant frequency as the pen information.
Data Source
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AI summary
An integrated circuit for an electronic pen is provided, the integrated circuit comprising: a first terminal that is configured to be connected to a first end of a first capacitor; a second terminal that is configured to be connected to a second end of the first capacitor; a plurality of second capacitors connected in parallel between the first and second terminals; a plurality of switches respectively disposed in series with the second capacitors; a power supply terminal connectable to an external device ; and a control circuit which, in operation, is adapted to control an on state and an off state of each of the switches and to generate a control signal for changing a capacitance of each of the second capacitors in accordance with a potential supplied by the external device to the power supply terminal. An electronic pen including the integrated circuit is also provided.