Touch Panel Conductive Path Layout for Simpler Pressed-Area Detection

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Solution Overview

Problem

Touch panels with complex structures for detecting depression positions, such as those with transparent conductive films on opposing substrates, are difficult to simplify and maintain for effective pressure sensing.

Innovation Solution

A touch panel design where a first conductive path is disposed on one sheet and a second conductive path and pressure-detecting conductive paths are on another sheet, allowing for simplified detection of pressed areas without the need for transparent conductive films on both sheets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If transparent conductive films are disposed on both upper and lower substrates with parallel wires for detection, then depression positions can be detected, but the structure becomes complicated

Engineering Contradiction:
Improvedetection of depression positionsVSAvoidstructure of touch panel
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts the detection function from the traditional dual-substrate parallel wire structure. By placing only the pressure-detecting conductive path on the lower substrate and using a single conductive path on the upper substrate, the complex detection structure is simplified while maintaining detection capability through alternative electrical connection methods.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The conductive paths are segmented into distinct functional components: a first conductive path on the upper substrate for signal transmission, and a second conductive path with pressure-detecting segments on the lower substrate. This segmentation allows each component to perform its specific function efficiently, reducing overall structural complexity.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If traditional resistive touch panel structure with multiple conductive layers is used, then depression detection is enabled, but manufacturing and maintenance become difficult

Engineering Contradiction:
Improvedetection of pressed areasVSAvoidstructure assembly and maintenance
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The invention removes the requirement for transparent conductive films on both substrates. By extracting this redundant component and using a simplified single-substrate configuration for pressure detection, manufacturing processes become less complex and maintenance becomes easier while preserving detection accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the electrical configuration parameters by using a single conductive path on one substrate instead of multiple parallel wires on both substrates. This parameter change simplifies the manufacturing process and assembly while maintaining the ability to detect pressed areas through electrical connection changes.

Inventive Principle:
Principle #35Parameter changes

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 design simplifies the touch panel structure while enabling effective detection of pressed areas by forming an electric circuit upon pressure application, allowing for accurate determination of pressure-sensing areas without additional sensors.

Implementation Method 1

a pressure-detecting conductive path 115 which is electrically connected with the second conductive path 114 and extends in a direction intersecting the first conductive path 113 as viewed from the front, wherein upon pressing of any of the pressure-sensing areas 105a to 105i, one of the pressure-detecting conductive paths 115a to 115i corresponding to the pressed one of the pressure-sensing areas 105a to 105i is in electrical contact with the first conductive path 113

Methodology Applied
Scientific EffectPressure-sensitive electrical conduction: Piezoresistive Effect

Data Source

PatentEP3121696B1Touch panel, input apparatus, remote control apparatus, and touch panel manufacturing method
Publication Date: 2023.09.13 MITSUBISHI ELECTRIC CORP
  • EP3121696B1 patent drawingFigure 1
  • EP3121696B1 patent drawingFigure 2
  • EP3121696B1 patent drawingFigure 3

AI summary

A touch panel (106) includes a first sheet (111) and a second sheet (112) opposing each other with a gap therebetween. A first conductive path (113) is formed on a main surface of the first sheet (111) and a second conductive path (114) is formed on a main surface of the second sheet (112), and the main surfaces oppose each other. The second conductive path (114) is spaced apart from the first conductive path (113) as viewed in a direction perpendicular to the first sheet (111). Pressure-detecting conductive paths (115a to 115i) electrically connected to the second conductive path (114) are disposed on the main surface of the second sheet (112). The pressure-detecting conductive paths (115a to 115i) each intersect the first conductive path (113) as viewed in the direction perpendicular to the first sheet (111).