Touch Sensing System Contour Detection for Palm Rejection

Solution Overview

Problem

Conventional capacitive touch sensing systems often experience errors when touched by a palm or wrist, leading to complex operations and longer processing times due to the need for precise detection of touch points.

Innovation Solution

A touch sensing system with a matrix of touch sensing units, a driving apparatus, and a processing circuit that defines a matrix of sensing values, scans for non-zero elements, and calculates the size of an object's contour by modulating search directions within predetermined angles, simplifying the detection process and reducing operation time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional capacitive touch sensing system is used to detect touch points, then touch detection capability is provided, but errors occur when touched by palm or wrist leading to complex operations and long processing times

Engineering Contradiction:

Improvetouch detection accuracyVSAvoidoperation time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts only the essential contour information of the touched object by scanning for non-zero elements and connecting them, rather than processing all sensing data. This extraction of key features (contour points) eliminates unnecessary processing steps and reduces operation time while maintaining detection accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the touch detection process into distinct phases: scanning for non-zero elements, identifying contour points, and calculating contour size. This segmentation allows the system to focus computational resources on critical steps and skip unnecessary processing, thereby reducing overall operation time.

Inventive Principle:

Principle #1Segmentation

2Reliability

If conventional capacitive touch sensing system is used, then touch detection is provided, but complex operations are required to eliminate wrong touching effects

Engineering Contradiction:

Improvetouch detection accuracyVSAvoidoperation complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential contour information of the touched object by scanning for non-zero elements and connecting them, rather than processing all sensing data. This extraction of key features (contour points) eliminates unnecessary processing steps and reduces operation time while maintaining detection accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of trying to eliminate wrong touches by complex filtering operations, the patent inverts the approach by directly identifying contour points through sequential scanning and connection. This inverted methodology simplifies the operation by focusing on what the contour should be rather than what to remove.

Inventive Principle:

Principle #13The other way round (Inversion)

3Loss of information

If conventional touch sensing system processes all sensing data, then complete touch information is obtained, but long processing time is required

Engineering Contradiction:

Improvetouch information completenessVSAvoidprocessing time

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

The patent extracts only the essential contour information of the touched object by scanning for non-zero elements and connecting them, rather than processing all sensing data. This extraction of key features (contour points) eliminates unnecessary processing steps and reduces operation time while maintaining detection accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by scanning only necessary rows and columns to identify contour points rather than processing the entire sensing matrix. This partial processing approach maintains sufficient touch information while significantly reducing processing time.

Inventive Principle:

Principle #16Partial or excessive action

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 effectively reduces errors and operation time by accurately detecting touch contours and eliminating edge noise, resulting in a smooth convergence zone for touched areas.

Implementation Method 1

the capacitive touch sensing system... a touch panel includes a plurality of touch sensing units arranged in form of a matrix

Methodology Applied

Scientific EffectCapacitive sensing: Capacitance

Data Source

PatentUS9134847B2Touch sensing system and operation method thereof

Publication Date: 2015.09.15 AU OPTRONICS CORP

AI summary

A touch sensing system includes a touch panel, a driving apparatus and a processing circuit. The touch panel includes a plurality of touch sensing units arranged in form of a matrix. The driving apparatus is configured to drive the touch sensing units, receive a sensing signal from each of the touch sensing units, convert each of the received sensing signals to have a digital format and output the digital sensing signals. The processing circuit is configured to define a matrix of sensing value according to values of the received sensing signals and positions of the respective touch sensing units, scan the non-zero elements in the matrix by a predetermined mean, refer all the located non-zero elements to as a part of the contour of the object and calculating a size of a contour of an object. An operation for the touch sensing system is also provided.