Active Stylus Position Detection With Triggered Signal Exchange
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Solution Overview
Problem
Conventional position detection devices with built-in power source styluses suffer from excessive battery consumption due to continuous signal transmission, especially when the unique ID data transmission is required, which is inefficient and power-intensive.
Innovation Solution
A position detection device that utilizes distinct control signals with different frequencies or modulation methods to control the stylus, allowing it to operate in low-power reception modes and selectively transmit position indicating signals, reducing unnecessary ID data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stylus continuously transmits signals including unique ID data to the tablet, then the tablet can maintain recognition of the position indicator, but the battery consumption of the stylus becomes excessive
Solution Approach 1:
The patent implements periodic action by having the tablet transmit control signals at specific intervals and the stylus transmit position indicating signals only in response to these control signals. This replaces continuous transmission with periodic, event-driven transmission, maintaining recognition reliability while significantly reducing battery consumption during non-use periods
Solution Approach 2:
The patent extracts the unique ID transmission from continuous operation by implementing it only once during initial pairing or when requested by the tablet through specific control signals. This removes the unnecessary continuous transmission of ID data that was consuming battery power in the conventional approach
2Reliability
If the stylus transmits unique ID data repeatedly to the tablet, then the tablet can maintain unique identification of the position indicator, but the time required for signal transmission increases
Solution Approach 1:
The patent applies preliminary action by establishing the unique ID connection once during initial pairing between the stylus and tablet. After this preliminary action, the unique ID does not need to be re-transmitted, as the tablet already has it stored and can continue to identify the stylus using this pre-established information
Solution Approach 2:
The patent extracts unique ID transmission from the regular signal exchange by implementing it only when necessary (initial pairing or when explicitly requested). This removes redundant ID transmission cycles, significantly reducing the time required for complete signal exchange while maintaining reliable unique identification
3Productivity
If the stylus operates in one-way communication mode transmitting signals continuously, then the tablet can receive position information without interruption, but the stylus cannot optimize power usage
Solution Approach 1:
The patent implements dynamics by enabling bidirectional communication where the tablet can send control signals to the stylus and the stylus can send position information in response. This dynamic, two-way communication allows the system to adapt power usage based on actual needs, with the stylus entering low-power states when no position updates are required while maintaining the ability to transmit position information without interruption when needed
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 significantly reduces power consumption by minimizing unnecessary signal transmission and optimizing power usage in the stylus, thereby extending battery life.
Implementation Method 1
a position detection device that obtains a position pointed to by a position indicator on a tablet through capacitive coupling between the tablet and the position indicator
Data Source
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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 1 includes a tablet 3 and the stylus 2 having a built-in power source, which are capable of bi-directional transmission and reception of signals through capacitive coupling therebetween. The tablet 3 is configured to transmit a trigger signal US_trg and then transmit a command signal US_cmd to the stylus 2. The trigger signal US_trg causes the stylus 2 to start its command information receiver to receive the command signal US_cmd including information for controlling the stylus 2.