Input Sensing Device with Integrated Strain Gauges

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Solution Overview

Problem

Current display devices, particularly LCDs and OLEDs, face challenges in effectively integrating touch sensing and pressure detection without compromising optical visibility or increasing device thickness.

Innovation Solution

The integration of an input sensing panel with a base layer, sensing electrodes, strain gauges, and signal lines on a display panel, which senses touch position and pressure using mutual-cap and self-cap methods, and measures resistance changes to detect touch pressure, eliminating the need for a separate pressure sensor module.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a separate pressure sensor module is added to detect touch pressure, then pressure detection capability is improved, but device thickness increases

Engineering Contradiction:
Improvepressure detection capabilityVSAvoiddevice thickness
Core Design Contradiction:
Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent combines the pressure sensing function with the existing touch panel structure by integrating strain gauges into the touch panel substrate. This merging eliminates the need for a separate pressure sensor module, thereby maintaining pressure detection capability while avoiding increased device thickness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The touch panel substrate is designed to serve multiple functions: it acts as both the touch sensing element and the pressure sensing element through the integrated strain gauges. This multi-functionality allows pressure detection without adding separate components that would increase thickness.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If multiple sensing layers are added to detect both touch and pressure, then sensing capability is improved, but optical visibility deteriorates

Engineering Contradiction:
Improvesensing capabilityVSAvoidoptical visibility
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

The patent merges the pressure sensing function into the existing touch panel structure using strain gauges that are integrated into the substrate. This approach maintains sensing capability while using the same optical path as the display, thereby preserving optical visibility without adding separate sensing layers that would block light.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If separate touch and pressure sensor modules are used, then detection accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvedetection accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines touch sensing and pressure sensing into a single integrated structure. The strain gauges are embedded within the touch panel substrate, allowing both touch position and pressure to be detected through one unified system rather than requiring separate modules, thereby reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The touch panel substrate is designed to perform multiple sensing functions simultaneously. By making the substrate itself sensitive to both touch and pressure through integrated strain gauges, the system achieves dual functionality without the complexity of managing separate sensor modules.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution allows for simultaneous detection of touch position and pressure with reduced device thickness and improved optical visibility, enhancing user interaction without adding complexity or bulk to the display device.

Implementation Method 1

a first strain gauge ST1 and a second strain gauge ST2... measures resistance changes to detect touch pressure

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentEP3564801B1Input sensing device and display device including the same
Publication Date: 2025.01.01 SAMSUNG DISPLAY CO LTD
  • EP3564801B1 patent drawingFigure 1
  • EP3564801B1 patent drawingFigure 2
  • EP3564801B1 patent drawingFigure 3~4

AI summary

An input sensing device includes a plurality of first sensing electrodes having a plurality of first sensor units extending in a first direction. A plurality of second sensing electrodes has a plurality of second sensor units extending in a second direction different from the first direction. A first strain gauge includes a first force electrode located proximate to a first electrode of the plurality of first sensing electrodes. A second force electrode is located proximate to a second electrode of the plurality of first sensing electrodes. A first connecting electrode connects to both of the first force electrode and the second force electrode.