Capacitive Stylus Pen Touch Panel Signal Detection
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Solution Overview
Problem
Existing mobile terminals require a separate power transmission device with an induction coil to supply power to stylus pens, increasing cost and thickness, and facing issues with energy discharge due to resistance in touch panel electrodes, which hampers efficient signal transmission and detection.
Innovation Solution
A mobile terminal using capacitive coupling between a touch panel and a stylus pen for electric signal transmission and reception, eliminating the need for a separate power transmission device, and employing a simplified circuit with an LC circuit in the stylus pen for resonance without power consumption, allowing simultaneous drive of all touch panel electrodes for improved detection speed and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a separate power transmission device with induction coil is installed beneath the LCD module to supply power to the stylus pen, then power can be transmitted to the stylus pen, but the cost and thickness of the cellular phone increase
Solution Approach 1:
The touch panel electrodes are made to serve dual functions: both touch sensing and power transmission to the stylus pen. By using the existing electrode lines as both sensing elements and power transmission elements, the patent eliminates the need for separate induction coils and power transmission devices, thereby reducing device complexity and thickness while maintaining the power transmission capability.
Solution Approach 2:
The patent merges the power transmission function with the touch sensing function by using the same electrode lines for both purposes. This consolidation of functions into a single component (the touch panel electrodes) removes the need for separate power transmission hardware, directly addressing the contradiction between power transmission capability and device complexity.
2Use of energy by moving object
If the electrode line of touch panel is made of coil to transmit power, then power can be supplied to stylus pen, but resistance component is large causing energy to be discharged as heat and circuit fails to resonate
Solution Approach 1:
The patent changes the physical parameters of the electrode lines by making them wider and using materials with lower resistance. This parameter modification reduces the resistance component in the power transmission path, minimizing energy loss as heat and enabling successful circuit resonance between the touch panel and stylus pen.
Solution Approach 2:
The patent replaces the traditional induction coil-based power transmission system with a direct capacitive coupling system using wide, low-resistance electrode lines. This substitution eliminates the inductive coupling mechanism that suffers from high resistance and energy loss, achieving more efficient power transmission through direct capacitive interaction.
3Use of energy by moving object
If a separate dedicated panel for power supply is provided in the main body to supply power wirelessly to stylus pen, then power can be supplied to stylus pen, but cost and thickness of cellular phone increase
Solution Approach 1:
The touch panel electrodes are designed to perform multiple functions simultaneously: touch sensing, power transmission to stylus pen, and signal communication. This multi-functionality eliminates the need for separate dedicated power supply panels, directly reducing manufacturing costs while maintaining wireless power supply capability.
Solution Approach 2:
The existing touch panel infrastructure serves the additional function of power transmission without requiring separate dedicated components. The touch panel electrodes self-serve the dual purpose of sensing and power transmission, eliminating the need for additional dedicated power supply panels and reducing overall manufacturing complexity and cost.
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 reduces manufacturing costs and thickness by eliminating the need for a separate power supply unit, enhances detection speed and accuracy of the stylus pen location using capacitive coupling, and increases the magnitude of electric signals transmitted and received, thereby improving touch recognition.
Implementation Method 1
capable of transmitting and receiving an electric signal between the touch panel and the stylus pen using capacitive coupling
Implementation Method 2
employing a simplified circuit with an LC circuit in the stylus pen for resonance without power consumption
Data Source
AI summary
A mobile terminal including a touch panel including a plurality of touch panel electrodes; a stylus pen configured to perform transmission and reception of an electric signal with the touch panel using capacitive coupling and without using a separate power supply to the stylus pen; and a controller configured to, when the electric signal is received from the stylus pen through the capacitive coupling, detect a location of the stylus pen with respect to the touch panel based on signal magnitudes of at least two touch panel electrodes from which the electrical signal is detected.