Touch Stylus Signal Transmission via Dual Duty Cycle Modulation
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Solution Overview
Problem
Existing stylus technologies face challenges in accurately transmitting signal values to touch sensitive processing apparatuses due to variations in touch electrode density and hover distances, leading to errors in signal strength and duty cycle ratios.
Innovation Solution
The implementation of a transmitter that modulates electrical signals with a first duty cycle in a reference signal time period and a second duty cycle in a modulation signal time period, where the ratio of the second duty cycle to the first duty cycle corresponds to the signal value, and the lengths and amplitudes of both periods are kept constant, allowing for precise signal value transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a stylus transmits electric signals via an electrode to a touch panel, then signal transmission is achieved, but signal accuracy deteriorates due to variations in touch electrode density and hover distances
Solution Approach 1:
The patent divides signal transmission into periodic time periods with different duty cycles. A first duty cycle transmits reference signals while a second duty cycle transmits modulation signals carrying the actual signal value. This periodic structure allows the receiving apparatus to compare signals across different time periods, compensating for variations in electrode density and hover distance, thereby improving measurement precision while maintaining reliability
Solution Approach 2:
The patent implements a feedback mechanism where the receiving apparatus detects characteristic values from both reference and modulation signals, calculates ratios between them, and uses this ratio information to determine the actual signal value. This feedback loop compensates for signal strength variations caused by environmental factors, resolving the contradiction between measurement precision and reliability
2Productivity
If duty cycle ratios are used to represent signal values, then transmission efficiency is improved, but measurement accuracy deteriorates due to environmental variations
Solution Approach 1:
The patent introduces a reference signal as an intermediary element. The reference signal transmitted during the first duty cycle serves as a mediator that carries information about the transmission environment (electrode density, hover distance). By comparing the modulation signal with this intermediary reference signal, the system can extract accurate signal values while maintaining high transmission efficiency through duty cycle modulation
3Device complexity
If single modulation is used for signal transmission, then device complexity is reduced, but information capacity is limited
Solution Approach 1:
The patent segments the signal transmission process into distinct time periods with different functions. The first time period transmits reference signals while the second time period transmits modulation signals. This segmentation allows the system to maintain relative simplicity in the modulation mechanism while effectively transmitting multiple pieces of information (reference information and signal value information) across different time segments, thereby increasing information capacity without significantly increasing device complexity
Data Source
AI summary
A touch sensitive processing method comprising: sensing a first characteristic value of the electrical signals received in a reference signal time period; sensing a second characteristic value of the electrical signals, having a first number of waves, received in a first modulation signal time period; sensing a third characteristic value of the electrical signals, having a second number of waves, received in a second modulation signal time period; calculating a first ratio of the second characteristic value and the first characteristic value and calculating a second ratio of the third characteristic value and first characteristic value; and calculating the signal value according to a function of the first ratio, the second ratio, the first number of waves and the second number of waves.