Active Stylus Control Signals for Lower Battery Transmission Load
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Solution Overview
Problem
Conventional styluses with built-in power sources suffer from excessive battery consumption due to continuous signal transmission and transmission of unnecessary unique identification data, leading to prolonged signal transmission times.
Innovation Solution
A position detection device utilizing capacitive coupling between a tablet and a position indicator, where the position indicator receives distinct control signals to manage power consumption by adjusting transmission modes and only transmitting necessary data, including a resonance circuit for signal generation and a transformer for efficient power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stylus continuously transmits signals to maintain one-way communication with the tablet, then the position detection function is maintained, but the battery consumption becomes excessive
Solution Approach 1:
The patent implements bidirectional communication where the tablet periodically transmits control signals to the stylus, and the stylus transmits position information only when needed or triggered. This periodic interaction replaces continuous unidirectional transmission, allowing the stylus to enter low-power states between communications while maintaining detection functionality.
Solution Approach 2:
The communication mode dynamically switches between stylus-transmitted position data and tablet-controlled signal transmission. The system adapts the transmission direction and frequency based on operational requirements, enabling the stylus to reduce power consumption by not continuously transmitting when the tablet actively controls the communication rhythm.
2Reliability
If the stylus transmits unique ID data repeatedly to ensure recognition, then the identification reliability is improved, but the signal transmission time increases
Solution Approach 1:
The unique ID and other identification data are transmitted in advance during the initial connection phase or when the tablet requests updated information. Once recognized, the tablet stores this information and uses it for subsequent communications, eliminating the need for repeated transmission of the same identification data during normal operation.
Solution Approach 2:
The tablet provides feedback to the stylus regarding recognition status and information reception. When the tablet has already recognized the stylus and stored its unique ID, it signals this state, allowing the stylus to stop transmitting redundant identification data, thus reducing transmission time while maintaining reliable identification.
3Loss of information
If the stylus transmits all available data including unique ID every time, then the information completeness is improved, but the battery consumption increases
Solution Approach 1:
The patent extracts and separates essential position information from redundant identification data. The stylus transmits only the necessary position coordinates and minimal operational data during normal use, while unique ID and other static identification information are transmitted only when requested by the tablet or during initial connection, reducing overall transmission volume and battery consumption.
Solution Approach 2:
Comprehensive data including unique ID is transmitted in advance during the connection establishment phase. Once the tablet has stored this information, subsequent communications require only brief position updates without repeating the full data set, thereby maintaining information completeness while significantly reducing ongoing power consumption.
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 device reduces battery consumption by minimizing unnecessary signal transmission and optimizing power usage, thereby extending the stylus's operational time.
Implementation Method 1
The position indicator generates a transmitting signal by resonance generated by a resonance circuit including a transformer primary coil and a capacitor
Implementation Method 2
capacitive coupling between the tablet and the position indicator
Data Source
AI summary
An active stylus is provided, which can reduce battery power consumption and reduce the time required for its signal transmission. A position detection device includes a tablet and the stylus having a built-in power source, which are capable of bi-directional transmission and reception of signals through capacitive coupling therebetween. The tablet is configured to transmit a trigger signal US_trg and then transmit a command signal US_cmd to the stylus. The trigger signal US_trg causes the stylus to start its command information receiver to receive the command signal US_cmd including information for controlling the stylus.