Active Stylus Electrostatic Communication Encoding
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Solution Overview
Problem
Touch-sensitive display devices face challenges in efficiently and robustly transmitting stylus information via electrostatic communication channels due to limited bandwidth and potential for data corruption, leading to delayed user responses and increased error likelihood.
Innovation Solution
The implementation of various encoding schemes such as binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), and differential encoding, along with forward error correction, to reduce the size and enhance the robustness of the stylus information report, allowing for more efficient and error-resistant data transmission within the limited bandwidth of the electrostatic communication channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If electrostatic communication channel is used for stylus information transmission, then power consumption is reduced and integration is improved, but bandwidth is limited and data corruption risk increases
Solution Approach 1:
The patent applies phase-shift keying (PSK) modulation to encode stylus information in the phase of electrostatic signals. By changing the phase parameter of the electrostatic communication channel (0° for logic 0, 180° for logic 1), the system achieves reliable data transmission through the limited-bandwidth electrostatic channel while maintaining low power consumption. This parameter transformation allows robust communication despite the inherent limitations of the electrostatic medium.
2Device complexity
If electrostatic communication channel is used for stylus information transmission, then device integration is improved, but transmission bandwidth is limited
Solution Approach 1:
The patent employs periodic sampling of the electrostatic communication channel at specific intervals (e.g., every 10 milliseconds) to transmit stylus information. This periodic action allows the system to efficiently utilize the limited bandwidth of the electrostatic channel by transmitting data in discrete time slots, thereby achieving adequate data transmission rates without requiring excessive bandwidth while maintaining simple device integration.
3Loss of time
If data transmission time is reduced, then user response lag is minimized, but transmission errors may increase due to rushed encoding
Solution Approach 1:
The patent performs preliminary encoding of stylus information using phase-shift keying modulation before transmission through the electrostatic channel. By pre-processing the data into phase-encoded signals (0° or 180° phase shifts representing logic 0 or 1), the system ensures that transmission can occur rapidly without sacrificing accuracy. This preliminary encoding preparation enables fast transmission that reduces user-perceptible lag while maintaining low error rates through robust phase-based encoding.
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
These encoding methods reduce the time required for data transmission, minimize errors, and improve the reliability of stylus information transfer, thereby enhancing the user experience by reducing lag and increasing the precision of touch input interactions.
Implementation Method 1
excite the electrode with a carrier signal to form an electrostatic communication channel
Data Source
AI summary
An active stylus includes an electrode and a controller. The controller is configured to 1) generate a report including stylus information represented by a plurality of bits including a first subset of bits and a second subset of bits, 2) encode the first set of bits differently than the second set of bits to reduce a size of the report, and 3) excite the electrode with a carrier signal to form an electrostatic communication channel, the carrier signal being modulated to transmit the report via the electrostatic communication channel.