Passive Stylus Resonance Circuit for Precise Touch Detection
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Solution Overview
Problem
Existing stylus pens, particularly those using electro magnetic resonance (EMR) and capacitive resonance methods, face challenges in signal transmission due to significant attenuation, leading to insufficient output signals and difficulty in precise touch recognition, which has hindered mass production.
Innovation Solution
A stylus pen design incorporating a resonance circuit with a ferrite core and a coil wound in multiple layers, along with a capacitor, and a touch input device with specific pattern arrangements, enables effective signal transmission and precise touch detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If EMR method or capacitive resonance method is used to achieve precise touch recognition, then measurement precision is improved, but device complexity increases due to additional sensor panels and driving ICs
Solution Approach 1:
The patent combines the capacitive touch sensor functionality with the EMR resonance functionality into a single integrated system. The touch sensor unit serves dual purposes: detecting touch inputs and enabling EMR signal transmission to the stylus pen. This merging eliminates the need for separate EMR sensor panels and driving ICs, reducing device complexity while maintaining precise touch recognition capability.
Solution Approach 2:
The touch sensor unit is designed to perform multiple functions simultaneously: it acts as both a capacitive touch detection device and an EMR signal transmission device. The same sensor unit that detects user touch inputs also transmits resonance signals to the stylus pen, enabling precise touch recognition without requiring additional dedicated EMR components.
2Measurement precision
If resonance frequency is matched to achieve sufficient signal amplitude, then measurement precision is improved, but signal transmission becomes difficult due to extreme attenuation
Solution Approach 1:
The patent introduces an intermediary coupling mechanism between the touch sensor unit and the stylus pen's resonance circuit. Instead of direct signal transmission that suffers from extreme attenuation, the system uses the touch sensor unit as an intermediary that can effectively couple resonance signals to the stylus pen through capacitive coupling, overcoming the signal transmission barrier.
Solution Approach 2:
The patent optimizes the resonance frequency parameters of the stylus pen's LC circuit to match the driving frequency of the touch sensor unit. By carefully selecting and adjusting the inductance and capacitance values in the stylus pen's resonance circuit, the system achieves resonant coupling that amplifies the signal amplitude, compensating for the natural attenuation and enabling precise signal detection.
3Adaptability or versatility
If active stylus pen is used to provide additional functions, then adaptability is improved, but cost increases due to battery and electronic components
Solution Approach 1:
The patent enables the passive stylus pen to perform functions previously requiring an active stylus by using the touch sensor unit's EMR resonance capability. The stylus pen's own body, when brought near the touch sensor unit, becomes part of the resonance circuit, allowing it to detect pressure, position, and other functions without requiring an external battery or complex electronic components. The system leverages the user's body and the stylus tip as part of the sensing mechanism.
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 enhances signal output and precision in touch recognition, addressing the limitations of existing stylus pens and enabling reliable interaction with touch input devices.
Implementation Method 1
a resonance circuit, and more particularly, to a touch input system including a sensor unit and interacting with a stylus pen and a controller for controlling a device
Implementation Method 2
an inductor part including a ferrite core disposed in the body part and a coil wound in multiple layers around at least a portion of the ferrite core
Data Source
AI summary
A pen and touch input system according to an embodiment of the present invention includes a touch input device including a sensor unit and a control unit for controlling the sensor unit and a stylus pen interacting with the touch input device.