Active Stylus Signal Encoding for Touch Screen Reporting Rate
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Solution Overview
Problem
Existing capacitive active stylus technologies have a low contact reporting rate, which degrades the writing and touch experience due to the time required to code coordinates and pressures, resulting in a slower response to user input.
Innovation Solution
A method that generates and transmits coded signals based on pressure information using different frequencies or prohibited transmission for each code bit, allowing the touch screen to identify code values and detect tip positions more efficiently, thereby increasing the contact reporting rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional coding methods are used to code coordinates and pressures, then the system can detect tip positions, but the detection time is long and the contact reporting rate is low
Solution Approach 1:
The pressure information is segmented into multiple code bits (n code bits) that can be independently encoded and transmitted. Each code bit represents a specific aspect of the pressure data, allowing parallel processing and faster detection. The segmentation enables the system to transmit pressure information more efficiently by breaking it down into manageable units that can be detected independently.
Solution Approach 2:
The invention changes the transmission parameter by using different frequencies (first frequency, second frequency) to represent different code values. This frequency-based encoding allows the touch screen to quickly identify code values by detecting the frequency of received signals, significantly reducing detection time compared to traditional amplitude or time-based coding methods.
2Measurement precision
If more code bits are used to represent pressure information accurately, then the precision of pressure detection improves, but the time required to transmit and detect the information increases
Solution Approach 1:
The invention uses periodic frequency changes to encode multiple bits of pressure information. By assigning different frequencies to different code values, the system can transmit multiple bits of precision pressure data in a single periodic transmission cycle, avoiding the need for sequential transmission of each bit and thus reducing total transmission time while maintaining high precision.
3Loss of information
If the system transmits both coordinate and pressure information separately, then complete tip position data is obtained, but the detection time increases and contact reporting rate decreases
Solution Approach 1:
The invention merges coordinate and pressure information transmission by using the same n coded signals for both purposes. The frequency-based encoding allows the touch screen to extract both position coordinates and pressure values from the same signal set, eliminating the need for separate transmission channels and significantly improving the contact reporting rate while maintaining complete information.
Data Source
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AI summary
Some embodiments of the present disclosure provide a method for transmitting and receiving a signal, a processor chip, an active stylus, and a touch screen. The method for transmitting a signal includes: acquiring, based on detected pressure information, codes representing pressure information and used to detect tip positions, where the code includes n code bits, n being an integer greater than 1 (101); generating n coded signals respectively corresponding to the n code bits(102); and transmitting each coded signal in the coded signals at the preset first or second frequency or prohibiting transmission of each coded signal in the coded signals, where the first frequency, the second frequency and prohibited transmission of the n coded signals relate to the pressure information (103). With the above method, the active stylus can output more coordinates of tip positions at a unit of time, and the touch screen can detect more coordinates of tip positions at a unit of time, thus improving the contact reporting rate.