Strain Gauge Display Panel for Touch Force Detection

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Solution Overview

Problem

Current touch input devices cannot effectively detect touch force without degrading the performance of the display module, which limits their ability to provide both touch position and force magnitude detection simultaneously.

Innovation Solution

A touch input device with a display panel that incorporates a strain gauge, where the strain gauge is directly formed on the panel, allowing for the detection of touch force based on resistance value changes, and a method for manufacturing this panel involving various substrate and material configurations, including liquid crystal or organic material layers and light shielding layers, to integrate the strain gauge seamlessly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If a strain gauge is added to detect touch force, then touch force detection capability is improved, but device complexity increases

Engineering Contradiction:

Improvetouch force detectionVSAvoiddisplay panel structure

Core Design Contradiction:

Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The strain gauge is integrated directly into the display panel structure by forming it on the inner surface of the second substrate layer, merging the force sensing function with the display structure. This eliminates the need for separate force sensing components and reduces overall device complexity despite adding touch force detection capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The second substrate layer serves multiple functions: it provides structural support for the display, serves as a mounting surface for the strain gauge, and maintains the display's optical properties. This multi-functionality reduces the need for additional components and simplifies the overall device architecture.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Difficulty of detecting and measuring

If a strain gauge is formed on the display panel, then touch force detection is enabled, but manufacturing complexity increases

Engineering Contradiction:

Improvetouch force detectionVSAvoiddisplay panel fabrication

Core Design Contradiction:

Difficulty of detecting and measuringVSEase of manufacture

Solution Approach 1:

The strain gauge is formed on the inner surface of the second substrate layer before final assembly of the display panel. This preliminary formation allows the strain gauge to be integrated into the substrate manufacturing process itself, avoiding complex post-assembly operations and simplifying overall manufacturing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The strain gauge uses electrical resistance changes to detect mechanical force, replacing complex mechanical force sensing mechanisms with simpler electrical measurements. This substitution enables touch force detection using standard electrical characterization techniques already available in display manufacturing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If multiple layers are added for strain gauge formation, then touch force detection accuracy is improved, but display module performance degrades

Engineering Contradiction:

Improvetouch force measurementVSAvoiddisplay module performance

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The strain gauge is positioned locally on the inner surface of the second substrate layer at specific locations where force detection is needed, rather than adding comprehensive layers across the entire display. This localized approach provides sufficient measurement precision while minimizing impact on overall display performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The strain gauge uses partial coverage of the substrate inner surface, forming conductive patterns only in regions necessary for force detection. This partial action provides adequate touch force measurement capability without adding excessive material layers that would degrade display optical properties or reliability.

Inventive Principle:

Principle #16Partial or excessive action

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 the detection of touch force while maintaining the display module's performance, allowing for precise force measurement without compromising the display's clarity or functionality.

Implementation Method 1

The touch force is detected on the basis of a change of a resistance value of the strain gauge

Methodology Applied

Scientific EffectStrain gauge effect: Piezoresistive Effect

Data Source

PatentUS10809830B2Touch input device including display panel formed with strain gauge and display panel formed with strain gauge forming method

Publication Date: 2020.10.20 HIDEEP INC

AI summary

A touch input device capable of detecting a touch force may be provided that includes a display panel on which a strain gauge is directly formed. The touch input device detects the touch force on the basis of a change of a resistance value of the strain gauge.