Touch Screen Knob Rejection Area via Capacitance Sensing

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Solution Overview

Problem

Touch screens lack a palm rejection function when a knob is placed on them, leading to unintentional touches and disturbances during knob manipulation.

Innovation Solution

A touch sensitive processing apparatus and method that sets up a rejection area around a knob on the touch screen by calculating the center of the knob using mutual capacitance sensing, ignoring touching events within this area to prevent accidental inputs, and adjusting the rejection area based on the screen's attitude and presence of multiple knobs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a knob is placed on a touch screen, then the user can conveniently adjust variances or parameters, but unintentional touches around the knob would be inputted triggering unwanted functions

Engineering Contradiction:

Improveknob manipulationVSAvoidunintentional touches

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The touch screen is segmented into a rejection area (center region around the knob) and a non-rejection area (surrounding regions). The processor identifies the center region based on knob position and selectively applies different touch processing rules to each segment, allowing free manipulation in the center while preventing unintentional inputs in surrounding areas.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different quality characteristics are applied to different regions of the touch screen. The center region around the knob is configured with palm rejection functionality to allow hand manipulation without triggering touches, while surrounding regions maintain normal touch sensitivity. This local differentiation resolves the contradiction by making the touch response adaptive to spatial location.

Inventive Principle:

Principle #3Local quality

2Reliability

If palm rejection function is implemented to prevent unintentional touches, then accidental inputs are blocked, but computing resources and processing time are consumed

Engineering Contradiction:

Improvetouch input accuracyVSAvoidcomputing resource consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

Palm rejection processing is applied locally only to the center region around the knob rather than the entire touch screen. The processor determines touch events within this specific rejection area and applies palm rejection logic only there, significantly reducing the computational burden compared to global palm rejection while maintaining reliability where needed.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The touch processing system is segmented into regions requiring palm rejection (center area) and regions not requiring it (surrounding areas). By processing only the necessary segment, the system achieves reliable touch input accuracy without the full computational cost of applying palm rejection across the entire screen.

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If a rejection area is set up around the knob, then free manipulation is enabled, but the area inside the knob circumference is excluded from touch detection

Engineering Contradiction:

Improvehand manipulation freedomVSAvoidknob button function detection

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The rejection area is segmented into an inner region (inside knob circumference) and an outer region (annular area around the knob). The outer region is configured as the actual rejection area that blocks palm rejection, while the inner region maintains normal touch detection capability. This allows buttons inside the knob to function normally while still providing palm rejection protection in the surrounding area.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different touch processing characteristics are applied to different sub-regions within the rejection area boundary. The area inside the knob circumference is treated differently from the annular region around it, allowing button presses in the center to be detected while palm touches in the surrounding area are rejected. This local differentiation preserves both manipulation freedom and button functionality.

Inventive Principle:

Principle #3Local quality

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

Enables free manipulation of knobs without triggering unwanted functions, conserves computing resources, and adapts to various knob arrangements and screen orientations, enhancing user experience.

Implementation Method 1

mutual capacitance sensing, by the driving circuit and the sensing circuit, via the touch electrodes to get one or more continuous images of the touch panel

Methodology Applied

Scientific EffectMutual capacitance sensing: Capacitance

Data Source

PatentUS12164764B2Touch sensitive processing apparatus, electronic system and touch sensitive processing method thereof

Publication Date: 2024.12.10 EGALAX EMPIA TECH INC

AI summary

According to one embodiment of the present application, a touch sensitive processing method is provided. The touch sensitive processing method, comprising: mutual capacitance sensing via touch electrodes of a touch panel to get one or more continuous images of the touch panel; calculating a center of circle corresponding to a knob placed on the touch panel according to the one or more continuous images; and when the center of circle is detected, setting up a rejection area corresponding to the center of circle.