Touch Panel Spatial Resolution via Asymmetric Component Grouping

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Solution Overview

Problem

Conventional touch-sensitive apparatuses face limitations in achieving uniform spatial resolution across the touch surface, particularly near the center line, due to the convergence of propagation paths, which results in reduced detection accuracy and increased noise artifacts.

Innovation Solution

The apparatus systematically arranges emitters and detectors in spatially separate groups along the perimeter of the touch surface, with varying inter-group and intra-group spacings, to distribute propagation paths more evenly and reduce convergence, thereby enhancing spatial resolution and uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If emitters and detectors are arranged in alternating rows around the periphery of the touch surface, then the grid of propagation paths can be formed, but the spatial resolution is non-uniform particularly near the center line due to convergence of propagation paths

Engineering Contradiction:
Improvespatial resolutionVSAvoiduniformity of spatial resolution
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies asymmetry by transitioning from alternating emitter-detector rows to separate groups of emitters and detectors. This asymmetric arrangement prevents the convergence of propagation paths at the center line, thereby achieving uniform spatial resolution across the entire touch surface including the center region.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent distributes emitters and detectors in spatially separate groups around the periphery rather than in alternating rows. This dimensional reorganization of component placement changes the propagation path geometry, eliminating the convergence issue and improving uniformity of spatial resolution.

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

2Measurement precision

If the number of emitters and detectors is increased to improve spatial resolution, then detection accuracy improves, but the device complexity and cost increase

Engineering Contradiction:
Improvespatial resolutionVSAvoidnumber of components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the geometric parameters of component arrangement - specifically the spacing between emitters/detectors within groups and between groups. By optimizing these parameters, the system achieves improved spatial resolution without increasing the number of components, as the new arrangement creates more uniformly distributed propagation paths.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates different local arrangements within the component groups - emitters are placed in specific groups at specific locations around the periphery, and detectors are placed in corresponding groups. This localized optimization of component placement ensures uniform propagation path distribution across different regions of the touch surface.

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

This arrangement increases the spatial resolution and reduces noise artifacts by distributing intersection points more uniformly, allowing for more accurate detection of objects across the touch surface without increasing the number of components, and improves the reliability of image reconstruction algorithms.

Implementation Method 1

Light generated by a plurality of emitters is coupled into the panel so as to propagate by total internal reflection (TIR) between the boundary surfaces to a plurality of detectors

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

An object that touches one of the boundary surfaces ('the touch surface') will attenuate ('frustrate') the light on one or more propagation paths and cause a change in the light received by one or more of the detectors

Methodology Applied
Scientific EffectFrustrated total internal reflection: Total Internal Reflection

Data Source

PatentEP2852880B1Touch-sensitive apparatus with improved spatial resolution
Publication Date: 2019.08.14 FLATFROG LAB
  • EP2852880B1 patent drawingFigure 1A~2
  • EP2852880B1 patent drawingFigure 3A~3D
  • EP2852880B1 patent drawingFigure 3E~3H

AI summary

A touch-sensitive apparatus is configured to propagate energy inside a panel (1) so as to define a grid of transmission paths across a touch surface (4) of the panel (1). The apparatus comprises a first subset of components on a first end of the touch surface (4), and a second subset of components on a second end which is opposite to and parallel with the first end. The components include emitters and detectors, each emitter being operable for propagating a diverging energy beam (e.g. radiation) across the touch surface (4) inside the panel (1), and each detector being operable for detecting transmitted energy from at least two emitters. The components in at least one of the first and second subsets are systematically arranged in spatially separate groups along at least one of the first and second ends, so as to achieve a reduced spacing and/or an increased uniformity of the transmission paths along a center line between the first and second ends compared to an equidistant arrangement of all components.