Stylus Pen Multiplexing Circuit for Pressure Data
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Solution Overview
Problem
Existing touch panel systems require additional components and increased complexity to transmit writing pressure information from a stylus pen, including a booster circuit for voltage boosting, which increases costs and complexity, and require high-frequency oscillation performance and high withstanding voltage performance.
Innovation Solution
A touch panel system with a stylus pen that uses a multiplexing circuit to combine two driving voltages into a single multiplexed voltage, eliminating the need for time-difference code transmission and high-frequency oscillation performance, and allowing the touch panel controller to detect position and additional information from the stylus pen without additional circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If time difference method is used to transfer writing pressure information, then writing pressure information can be transmitted, but output signal frequency deteriorates and waiting time is required
Solution Approach 1:
The patent merges position information and writing pressure information into a single code structure. The pen point drives a single code that simultaneously encodes both position coordinates and pressure level, eliminating the need for separate time-multiplexed transmission and maintaining high output signal frequency.
Solution Approach 2:
The single code generated by the pen point serves multiple functions: it encodes position information (X and Y coordinates) and writing pressure information simultaneously. This multi-functional code replaces the need for separate codes for different information types.
2Loss of information
If time difference method is used to transfer writing pressure information, then writing pressure information can be transmitted, but code generation circuit complexity increases
Solution Approach 1:
The patent combines multiple information encoding functions into a single code generation process. The pen point generates one code that integrates position and pressure data, eliminating the need for separate code generation circuits for different information types.
3Loss of information
If writing pressure information is transferred by changing driving voltage, then writing pressure information can be transmitted, but booster circuit and high voltage endurance process are required
Solution Approach 1:
The patent replaces the electrical voltage-based pressure encoding mechanism with a code-based encoding mechanism. Instead of varying driving voltage amplitude to represent pressure, the system uses discrete code values that encode pressure information, eliminating the need for voltage boosting circuits and high-voltage endurance processes.
4Loss of information
If high-frequency oscillation performance is required, then writing pressure information can be transmitted, but device complexity and cost increase
Solution Approach 1:
The patent changes the encoding parameter from frequency-based (requiring high-frequency oscillation) to code-based (using discrete digital values). The pen point outputs code sequences that directly represent pressure information without requiring high-frequency oscillation performance, simplifying the device requirements.
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 system simplifies the configuration for transmitting additional information from the stylus pen to the touch panel controller, reducing the need for complex circuitry and high-performance components, while effectively detecting the stylus pen's position and writing pressure information.
Implementation Method 1
a multiplexing circuit which drives a pen point of the stylus pen with a multiplexed voltage obtained by multiplexing the first driving voltage and the second driving voltage
Implementation Method 2
a variable resistor one end of which is connected to a first terminal to which the first driving voltage is applied and whose resistance value changes based on information regarding the stylus pen
Implementation Method 3
a touch panel which has a plurality of electrostatic capacitances formed at respective intersections of a plurality of first signal lines and a plurality of second signal lines
Data Source
AI summary
A touch panel system (1) according to one aspect of the invention includes: a stylus pen (15) including a drive circuit (26) that generates a first driving voltage based on a first code sequence and a second driving voltage based on a second code sequence, and a sensor circuit (40) that drives a pen point (38) with a multiplexed voltage obtained by multiplexing the first driving voltage and the second driving voltage; and a touch panel controller (2) that detects a position of the stylus pen (15) touching a touch panel.