Active Stylus DSSS Signal Reception via Coupling Capacitor
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Solution Overview
Problem
Existing active stylus touch systems face challenges in receiving direct sequence spread spectrum (DSSS) signals due to impedance limitations in touch screen sensors, which restrict spectrum spreading and are not suitable for systems with strict size and power consumption requirements.
Innovation Solution
A method involving a coupling capacitor between the active stylus and touch screen to receive and parse DSSS signals, utilizing a pre-amplifier circuit, hysteresis comparing circuit, and digital demodulating circuit to restore and demodulate the signals, allowing for efficient information interaction with reduced hardware resources and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DSSS signal is transmitted through high-frequency antenna in radio frequency environment, then signal transmission can be achieved, but impedance of screen sensor limits spectrum spreading and makes it inapplicable to active stylus touch system
Solution Approach 1:
The patent introduces a coupling capacitor as an intermediary component between the touch screen sensor and the active stylus. This capacitor enables capacitive coupling for DSSS signal transmission, serving as a mediator that bridges the gap between the screen sensor and stylus receiver without requiring direct electrical contact or high-frequency antenna implementation, thus resolving the impedance limitation issue.
Solution Approach 2:
The patent replaces the traditional radio frequency antenna-based electromagnetic transmission system with a capacitive coupling system. By substituting the mechanical/electromagnetic antenna structure with an electrical capacitive coupling mechanism, the system achieves DSSS signal transmission suitable for the constraints of active stylus touch systems while maintaining signal integrity.
2Reliability
If traditional high-frequency antenna mode is used for DSSS signal transmission, then signal can be transmitted, but circuit size and power consumption requirements cannot be met
Solution Approach 1:
The patent extracts and eliminates the high-frequency antenna component from the transmission system. By removing this bulky and power-intensive component and replacing it with a capacitive coupling mechanism integrated into the existing touch screen sensor, the system achieves signal transmission with significantly reduced circuit size and power consumption.
Solution Approach 2:
The coupling capacitor serves multiple functions simultaneously: it acts as the signal transmission medium for DSSS, maintains electrical isolation between screen and stylus, and integrates seamlessly with the existing touch screen sensor circuitry. This multi-functionality reduces the need for additional dedicated components, thereby minimizing overall circuit complexity.
3Adaptability or versatility
If coupling capacitor is used to receive DSSS signal, then signal reception is enabled in active stylus, but signal parsing requires pre-amplifier, hysteresis comparing, and digital demodulating circuits
Solution Approach 1:
The patent divides the signal parsing process into three distinct functional stages implemented by separate circuit modules: pre-amplification (signal strengthening), hysteresis comparing (signal threshold detection and restoration), and digital demodulation (information extraction). This segmentation allows each circuit to be optimized for its specific function while working together as an integrated signal reception system.
Solution Approach 2:
The pre-amplifier circuit performs preliminary signal amplification before the signal reaches the hysteresis comparing and demodulation stages. By strengthening the weak capacitive coupled signal in advance, the subsequent circuits can operate more effectively with adequate signal levels, ensuring reliable signal parsing while maintaining manageable circuit complexity.
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 approach enables effective DSSS signal transmission and reception in active stylus touch systems, meeting strict requirements on circuit size and power consumption, and is well-suited for interactive systems with a simple circuit structure and low resource usage.
Implementation Method 1
receive, through a coupling capacitor formed between the active stylus and the touch screen, the DSSS signal sent by the touch screen
Data Source
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AI summary
Some embodiments of the present disclosure provide a method and a system for transmitting a signal, an active stylus, a touch screen and a readable storage medium. The method for transmitting a signal comprises: receiving a DSSS signal sent by the touch screen through a coupling capacitor formed between the active stylus and the touch screen (201), where the DSSS signal is a spread-spectrum coded signal to be transmitted; and parsing the received DSSS signal to obtain the signal to be transmitted (202), which requires a small quantity of hardware resources and low power consumption, and can be well applied to an active stylus touch system.