Capacitive Touch Device with Optical System for 3D Object Detection

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Solution Overview

Problem

Capacitive touch devices struggle to differentiate between hovering and touching events for passive objects, such as fingers or passive styluses, and fail to precisely detect objects in 3D space around the device, manage multiple objects, and prevent undesired interactions with non-triggering objects.

Innovation Solution

An optical system connected to a processor is used to collect information on objects approaching and touching the capacitive touch device, allowing for 3D detection and classification of objects as triggering or non-triggering, enabling precise localization and execution of specific functions based on object type.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If capacitive touch devices use only capacitive sensing to detect objects, then the device structure remains simple, but the device cannot differentiate between hovering and touching events for passive objects

Engineering Contradiction:
Improveobject detection capabilityVSAvoiddetection system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines capacitive touch sensing with optical detection systems to create a hybrid detection mechanism. The optical system captures images of objects approaching the touch device, while the capacitive sensor detects touch events. By merging these two detection methods, the system can differentiate between hovering and touching events for passive objects, overcoming the limitation of capacitive-only detection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces an optical system as an intermediary component between the passive object and the capacitive touch device. The optical system captures visual information about the object's position and movement, which then complements the capacitive sensing data. This intermediary optical detection layer enables the system to distinguish hovering from touching without requiring the passive object to emit signals.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If capacitive touch devices increase detection sensitivity to detect hovering objects, then hovering detection improves, but false detection of non-triggering objects increases

Engineering Contradiction:
Improvehovering detection precisionVSAvoidfalse detection
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback mechanism where the optical system continuously monitors object approach and provides visual confirmation data to the detection algorithm. When an object hovers, the optical system captures its position and characteristics. The system cross-references this visual data with capacitive sensing data to confirm whether the hovering object is a triggering object (like a stylus) or a non-triggering object (like a finger or debris). This feedback loop reduces false detections by verifying object identity through multiple detection modalities.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If capacitive touch devices use optical systems to detect objects in 3D space, then object localization precision improves, but device complexity increases

Engineering Contradiction:
Improveobject localization precisionVSAvoidsystem structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transitions from traditional 2D touch surface detection to 3D spatial detection by incorporating an optical system. The optical system captures images that provide depth and spatial information about objects approaching the touch device. This adds a third dimension (height/distance from surface) to the detection capability, enabling precise 3D localization of objects while maintaining their 2D touch coordinates. The optical system's image data is processed to extract spatial coordinates that complement the flat touch surface data.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Reliability

If capacitive touch devices differentiate between triggering and non-triggering objects, then undesired interactions are prevented, but detection algorithm complexity increases

Engineering Contradiction:
Improveinteraction accuracyVSAvoiddetection algorithm complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality differentiation by analyzing specific characteristics of detected objects at their respective locations. The optical system captures visual features (shape, size, color, texture) of objects in different regions of the touch device. The detection algorithm compares these local visual characteristics against known profiles of triggering objects (styluses, fingers) versus non-triggering objects (debris, insects). By evaluating object properties locally rather than globally, the system can accurately classify objects and prevent undesired interactions without requiring excessively complex algorithms.

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 precise 3D detection of objects around the capacitive touch device with the same precision as 2D detection, effectively managing multiple objects and preventing undesired interactions by disabling touch functions for non-triggering objects.

Implementation Method 1

an optical system connected to this processor and arranged to collect information on this object

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

Capacitive touch devices comprise in general a touch controller comprising a processor and a detection circuit

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3242190B1System, method and computer program for detecting an object approaching and touching a capacitive touch device
Publication Date: 2019.11.06 ADVANCED SILICON
  • EP3242190B1 patent drawingFigure 1~3
  • EP3242190B1 patent drawingFigure 4~5
  • EP3242190B1 patent drawingFigure 6~7

AI summary

The present invention concerns a system (1) for detecting an object (100) approaching and touching a capacitive touch device (10), comprising: - the capacitive touch device (10), - a processor, - an optical system connected to the processor and arranged to collect information on the object (100), the processor being arranged so as to: - classify the object (100) as a triggering object or as a non-triggering object based on this information, - if the object is classified as a non-triggering object, disable the execution of touch functions of the capacitive touch device (10) at the latest when at least a part of the object (100) touches the capacitive touch device (10), - if the object is classified as a triggering object, at the latest when at least a part of the object touches the capacitive touch device (10), execute a predetermined function on the capacitive touch device (10).