Touch Sensing Device Dual-Scan Ghost Point Elimination
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Solution Overview
Problem
Existing touch screens face issues with low multi-touch sensitivity, incorrect ghost point recognition, and high power consumption due to inefficient sensing methods, which limit their performance and user experience.
Innovation Solution
A touch sensing device that employs a dual-sensing approach, initially scanning all touch sensors to detect presence and then performing a second, more precise scan only on detected touch inputs, using a block sensing method to reduce total sensing time and increase sensitivity, while minimizing power consumption by disabling unnecessary sensing areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all touch sensors are scanned sequentially to detect touch position, then touch position detection is achieved, but touch sensing time is prolonged and touch report rate is reduced
Solution Approach 1:
The patent divides the touch sensing process into two distinct phases: a first sensing step that scans all touch sensors to detect presence, and a second sensing step that scans only the detected touch inputs for precise position detection. This segmentation allows the system to maintain detection accuracy while significantly reducing the time required for complete sensing by avoiding redundant scanning of non-touch areas.
Solution Approach 2:
The patent implements partial sensing by performing the second sensing step only on the specific touch sensor locations that were detected as having touch inputs in the first sensing step. Instead of scanning all touch sensors again, the system applies sensing actions only where needed, thereby reducing overall sensing time while maintaining the ability to accurately detect touch positions.
2Productivity
If all touch sensors are scanned continuously to maintain high touch report rate, then responsiveness is improved, but power consumption increases
Solution Approach 1:
The patent employs periodic sensing actions where the first sensing step is performed continuously or at regular intervals to detect touch presence, and the second sensing step is performed periodically only when touch inputs are detected. This periodic approach allows the system to maintain high touch report rate by quickly identifying touch events while consuming less power by avoiding continuous full-screen scanning.
Solution Approach 2:
The patent extracts and isolates the power-intensive sensing operations to only those areas where touch inputs are detected. By taking out the second sensing step from the universal sensing process and applying it only to detected touch locations, the system maintains high responsiveness and touch report rate while significantly reducing overall power consumption.
3Measurement precision
If self capacitance touch screen scans X and Y lines to detect touch position, then touch detection is achieved, but ghost points are wrongly recognized as actual touch positions
Solution Approach 1:
The patent uses feedback from the first sensing step to guide the second sensing step. The results from scanning all touch sensors in the first step provide feedback information about where touch inputs are located, which then directs the second sensing step to focus only on those specific areas. This feedback mechanism helps eliminate ghost point recognition by ensuring that sensing resources are concentrated on actual touch locations rather than being distributed across the entire screen.
Solution Approach 2:
The patent performs a preliminary scanning action in the first sensing step to identify actual touch inputs before performing the detailed position detection in the second sensing step. This preliminary action allows the system to distinguish between actual touches and ghost points by first identifying which sensors show genuine touch signals, then focusing detailed analysis only on those confirmed locations.
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 enhances touch sensitivity and report rate, reduces power consumption, and accurately detects touch positions without ghost point errors, improving overall user interaction with touch screens.
Implementation Method 1
The self capacitance touch screen recognizes a touch sensor, which is positioned at a crossing of an X line and a Y line having a large change in capacitance before and after a touch operation, as a touch position
Data Source
AI summary
A touch sensing device includes a touch screen including Tx lines, Rx lines crossing the Tx lines, and touch sensors formed between the Tx lines and the Rx lines, and a touch screen driving circuit which senses all the touch sensors of the touch screen in a first sensing step to detect the presence or absence of a touch input, and then again senses the touch sensors, in which the touch input is detected as a first sensing result, in a second sensing step to detect a position of the touch input. When there is no touch sensor, in which the touch input is detected as the first sensing result, the touch screen driving circuit repeats the first sensing step.