Optical Touch Position Detection Using Multi-Module Intersection Verification

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Solution Overview

Problem

Existing optical touch modules struggle to accurately determine touch positions when multiple objects are detected, leading to positional deviations and the generation of ghost points, which can cause malfunction in touch operations.

Innovation Solution

A method and apparatus using multiple optical sensing modules with two optical sensing devices each, acquiring and processing sense information to determine touch ranges, calculating points of intersection, and verifying these points to filter out ghost points and accurately determine touch positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single optical touch module is used to detect touch positions, then the device complexity is low, but ghost points are generated when multiple touch objects are detected

Engineering Contradiction:

Improvenumber of optical touch modulesVSAvoidaccuracy of touch position detection

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system divides the touch detection function into multiple optical touch modules, each responsible for detecting touch positions from different directions. This segmentation allows the system to distinguish between actual touch points and ghost points by comparing detections from multiple modules, thereby improving reliability while managing complexity through functional division.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The processor acts as an intermediary that receives sense information from multiple optical touch modules, calculates potential touch positions, and verifies them by checking consistency across different modules. This intermediary processing step filters out ghost points while maintaining system complexity at an acceptable level.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If multiple optical touch modules are used to detect touch positions, then ghost points can be filtered out, but positional deviations occur due to differences in lens resolutions and positions

Engineering Contradiction:

Improveability to distinguish actual touched points from ghost pointsVSAvoidaccuracy of touch position measurement

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system dynamically adjusts parameters such as touch ranges and verification thresholds based on the specific configuration of each optical touch module. By adapting parameters to account for differences in lens resolutions and positions, the system maintains measurement precision while utilizing multiple modules to filter ghost points.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system accepts and utilizes the asymmetric characteristics of different optical touch modules (different resolutions, different positions) rather than requiring symmetric, identical configurations. The processor is designed to handle these asymmetries by implementing verification logic that accounts for module-specific variations, thereby maintaining precision across the system.

Inventive Principle:

Principle #4Asymmetry

3Reliability

If multiple optical sensing modules are used to verify touch positions, then ghost points are filtered out, but the processing complexity and time increase

Engineering Contradiction:

Improveaccuracy of touch position determinationVSAvoidtime for processing and verifying touch information

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The verification process is designed to stop once sufficient confidence is achieved rather than exhaustively checking all possible combinations. The system performs partial verification by checking a subset of modules or stopping early when a threshold is met, reducing processing time while maintaining reliability in determining actual touch positions.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system pre-calculates and stores parameters such as touch ranges, lens positions, and resolution characteristics for each optical sensing module before actual touch detection occurs. This preliminary preparation enables faster real-time verification by avoiding repeated calculations, thus reducing processing time while maintaining accurate ghost point filtering.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10698536B2Method of detecting touch position and touch apparatus thereof

Publication Date: 2020.06.30 WISTRON CORP

AI summary

A method for detecting multiple touch positions on a touch surface, which is applicable to a touch apparatus having multiple optical sensing modules, where each optical sensing module includes at least two optical sensing devices. The method includes: acquiring multiple pieces of sense information; determining multiple touch ranges for each piece of sense information; determining multiple points of intersection; selecting one of the pieces of sense information of which the touch ranges are used to calculate a greatest numbers of the points of intersection; for each touch range of the selected sense information, repeatedly selecting two of the points of intersection calculated using the corresponding touch range according to distances until the selected two points of intersection are verified as being located within the touch ranges of at least another one piece of sense information other than the selected sense information; and calculating the touch positions as actual touch positions according to the selected points of intersection when the selected points of intersection are verified as being located within the touch ranges of the at least another one piece of sense information other than the selected sense information.