Flexible Display Panel Force Sensing via Neutral Plane Electrodes

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Solution Overview

Problem

Existing force touch-control technologies in flexible display modules require additional components like sensor films or force-sensitive coils, leading to high costs and poor flexibility, making them unsuitable for light and bendable devices.

Innovation Solution

A flexible display panel with a stacked structure comprising a flexible substrate, a light-emitting device layer, and a polarizing layer, featuring upper-side and lower-side resistive force-sensitive electrodes positioned above and below a neutral plane, which senses user force by detecting resistance differences due to compressive and tensile stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional components such as sensor films or force-sensitive coils are used for force touch-control, then force sensing capability is improved, but device complexity and cost increase

Engineering Contradiction:

Improveforce sensing capabilityVSAvoidstacked layers complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the force sensing function with the existing display structure by integrating force-sensitive electrodes directly into the stacked layers of the flexible display panel. Instead of adding separate sensor films or coils, the force sensing capability is combined with the display's structural layers, thereby improving force sensing while avoiding increased device complexity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The stacked structure layers serve multiple functions: they provide both display functionality and force sensing capability. The force-sensitive electrodes are incorporated into the existing structural layers, making these layers universally functional for both display and sensing purposes, thus eliminating the need for additional dedicated sensing components

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If additional components such as sensor films or force-sensitive coils are used for force touch-control, then force sensing capability is improved, but manufacturing cost increases

Engineering Contradiction:

Improveforce sensing capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The force sensing function is merged with the existing display manufacturing process. The force-sensitive electrodes are fabricated using the same thin-film deposition and patterning techniques already employed for the display structure, eliminating the need for separate sensor component manufacturing and reducing overall production costs

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The existing structural layers of the flexible display panel serve the dual purpose of providing structural support and enabling force sensing. The stacked structure itself provides the sensing capability through its inherent mechanical properties and integrated electrodes, eliminating the need for additional expensive sensor components

Inventive Principle:

Principle #25Self-service

3Measurement precision

If stacked thickness is increased to accommodate additional sensing components, then force sensing capability is improved, but flexibility deteriorates

Engineering Contradiction:

Improveforce sensing capabilityVSAvoidflexibility

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The force sensing electrodes are merged with the existing thin structural layers of the flexible display panel. By integrating the sensing function into the existing stacked structure rather than adding thick separate sensing components, the patent maintains the panel's flexibility while achieving force sensing capability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent employs thin-film force-sensitive electrodes that are deposited as ultra-thin layers within the stacked structure. These thin films provide force sensing capability while maintaining the flexibility and bendability of the overall panel, avoiding the stiffness that would result from thicker rigid sensing components

Inventive Principle:

Principle #30Flexible shells and thin films

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 configuration enhances force-sensing sensitivity without increasing thickness, reduces costs by eliminating the need for additional sensors, and improves flexibility, enabling the use in light and bendable devices.

Implementation Method 1

at least one upper-side resistive force-sensitive electrode disposed on a layer above a neutral plane of the stacked structure, and at least one lower-side resistive force-sensitive electrode disposed on a layer below the neutral plane

Methodology Applied

Scientific EffectResistive stress sensing: Piezoresistive Effect

Data Source

PatentUS10461135B2Flexible display panel and fabrication method thereof, and flexible display device

Publication Date: 2019.10.29 SHANGHAI TIANMA MICRO ELECTRONICS CO LTD

AI summary

A flexible display panel, a flexible display device, and a fabrication method of the flexible display panel are provided. The flexible display panel comprises a stacked structure having a plurality of layers comprising a flexible substrate, a light-emitting device layer, and a polarizing layer stacked in a preset order. The flexible display panel further includes at least one upper-side resistive force-sensitive electrode disposed on a layer above a neutral plane of the stacked structure, and at least one lower-side resistive force-sensitive electrode disposed on a layer below the neutral plane.