Analog Voltage Scaling for Stylus Touch Sensor Data Transmission
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Solution Overview
Problem
Current touch sensors, particularly capacitive touch screens, face challenges in accurately detecting the presence and location of objects within a touch-sensitive area due to limitations in electrode configurations and data transmission methods, which can lead to resolution loss and inefficiencies in signaling speed.
Innovation Solution
The implementation of an array of drive and sense electrodes on substrates with specific patterns and materials, coupled with a touch-sensor controller that processes changes in capacitance to determine object presence and location, and the use of analog data transmission methods to enhance signaling speed and prevent resolution loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital data transmission is used between active stylus and touch-sensor device, then data can be transmitted in a standardized format, but resolution loss occurs and signaling speed is reduced
Solution Approach 1:
The patent replaces the digital data transmission system with an analog voltage signaling system. Instead of converting analog touch signals to digital format for transmission, the system directly transmits analog voltage signals from the active stylus to the touch-sensor device, eliminating the resolution loss and speed limitations associated with digital conversion and processing.
Solution Approach 2:
The patent changes the parameter of data representation from digital discrete values to analog continuous voltage levels. By transmitting actual analog voltage data that directly represents the touch sensor readings, the system maintains higher resolution and faster signaling compared to digital encoding schemes.
2Reliability
If voltage scaling is not implemented, then the communication circuitry can use fixed voltage levels, but the active stylus cannot overcome threshold voltages to transmit data reliably
Solution Approach 1:
The patent implements dynamic voltage scaling in the active stylus communication circuitry. The voltage level is adjusted based on the operational state - using higher voltages to overcome threshold barriers during data transmission and lowering voltages during normal operation. This dynamic adjustment ensures reliable communication while managing power consumption and circuit complexity.
3Measurement precision
If mutual capacitance measurement is used, then object presence can be detected, but resolution and precision are limited compared to self-capacitance
Solution Approach 1:
The patent segments the touch sensor into multiple independently controllable electrode groups, allowing the system to switch between mutual capacitance measurement mode for object presence detection and self-capacitance mode for higher precision location detection. This segmentation enables flexible measurement strategies without requiring a completely different electrode configuration.
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 solution enables precise detection of object presence and location within the touch-sensitive area while improving communication speed by transmitting actual analog data, reducing resolution loss and enhancing overall touch sensing performance.
Implementation Method 1
When an object touches or comes within proximity of the surface of the capacitive touch screen, a change in capacitance may occur within the touch screen at the location of the touch or proximity.
Data Source
AI summary
In one embodiment, an apparatus comprises a data-transmitting component and a data-receiving component. The data-transmitting component is operable to: select a set of first reference values and a set of second reference values respectively indicating a lower bound and an upper bound of a range of values; respectively represent the set of first reference values and the set of second reference values as a set of first pulses and a set of second pulses; represent a set of analog values as a set of third pulses, each third pulse having a third amplitude between the first amplitude of a corresponding first pulse and the second amplitude of a corresponding second pulse that is determined based on a percentage of the corresponding analog value within the range of values; and transmit the set of first pulses, the set of third pulses, and the set of second pulses to the data-receiving component.