Flexible Display Touch and Bending Sensing via Integrated Pressure Sensor

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Solution Overview

Problem

Conventional touch screen panels face challenges in minimizing thickness, recognizing non-finger touches, and sensing bending states, while also being costly and affecting image visibility due to separate manufacturing processes and rigid substrates.

Innovation Solution

A flexible display device with a pressure sensor portion integrated on a substrate, featuring intersecting first and second electrodes, a buffer layer, and strain sensors, connected to a flexible printed circuit board, allowing for touch and bending sensing, and improved manufacturing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional touch screen panel is used, then touch recognition is achieved, but the device thickness increases and non-finger touches cannot be sensed

Engineering Contradiction:

Improvetouch recognition capabilityVSAvoiddevice thickness

Core Design Contradiction:

Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent extracts the touch sensing function from a separate touch screen panel and integrates it directly into the display device structure. The pressure sensor portion is formed on the lower substrate, eliminating the need for a separate capacitive touch screen panel, thereby reducing overall device thickness while maintaining touch recognition capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the display device and pressure sensing functions into a single integrated structure. The pressure sensor portion is formed between the lower substrate and the pixel structure, combining display and touch sensing in one device layer, enabling both functions without increasing thickness

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

If a conventional touch screen panel is used, then touch contact is detected, but bending state sensing is not achieved

Engineering Contradiction:

Improvetouch contact detectionVSAvoidbending state sensing capability

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The pressure sensor portion serves multiple functions: it detects touch contact pressure and simultaneously senses bending states of the flexible display device. The same electrode structure responds to both external pressure and mechanical deformation, providing versatile sensing capability without additional components

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If separate manufacturing processes are used for display and touch components, then functional performance is achieved, but production cost increases

Engineering Contradiction:

Improvefunctional performanceVSAvoidproduction cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines display and pressure sensing manufacturing into a single integrated process. Both the pixel structure and pressure sensor portion are formed on the same lower substrate using similar fabrication steps, eliminating the need for separate assembly of touch screen panels and reducing production complexity and cost

Inventive Principle:

Principle #5Merging (Combining)

4Manufacturing precision

If a rigid substrate is used, then manufacturing precision is achieved, but image visibility and flexibility are reduced

Engineering Contradiction:

Improvesubstrate stabilityVSAvoidimage visibility

Core Design Contradiction:

Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The patent replaces rigid glass substrates with flexible organic substrates that maintain sufficient mechanical stability for manufacturing while allowing light transmission for improved image visibility. The flexible substrate enables better optical performance without compromising manufacturing precision through integrated electrode patterning

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

Enables thin, flexible, and cost-effective touch recognition with enhanced image visibility, capable of sensing non-finger contacts and bending states, while simplifying the manufacturing process and reducing production costs.

Implementation Method 1

The insulation layer may be made of a pressure conductivity changeable material

Methodology Applied

Scientific EffectPressure conductivity change: Piezoresistive Effect

Implementation Method 2

Some of the plurality of first and second electrodes may be implemented as strain sensors. The strain sensors may be formed as bending patterns

Methodology Applied

Scientific EffectStrain sensing: Elasticity

Data Source

PatentUS9904396B2Flexible display device having touch and bending sensing function

Publication Date: 2018.02.27 SAMSUNG DISPLAY CO LTD

AI summary

A flexible display device having a touch and bending sensing function includes a plurality of pixels on a display area of a first substrate, and a pressure sensor portion between the first substrate and the plurality of pixels, the pressure sensor portion including a plurality of first electrodes arranged in a first direction and a plurality of second electrodes above the first electrodes and arranged in a second direction.