Integrated Bending Sensor for Flexible Displays

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Solution Overview

Problem

The existing methods for integrating a bending sensor into flexible display devices result in increased manufacturing costs and thickness, as the sensor is typically manufactured separately and attached to the device, which does not align with the trend of providing slim, next-generation display devices.

Innovation Solution

A display device with a built-in bending sensor, where the curved unit and detection unit are integrated during the manufacturing process of the thin film transistor or display element, allowing the sensor to be formed using the same materials and processes as the device's components, thus eliminating the need for additional manufacturing steps and reducing thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a bending sensor is manufactured separately and attached to the flexible display device, then the bending detection function is achieved, but the manufacturing cost increases and the device thickness increases

Engineering Contradiction:
Improvebending detection functionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The bending sensor is merged with the flexible display device by forming the curved unit and detection unit during the same manufacturing process as the thin film transistor and display element. This integration eliminates separate manufacturing and attachment steps, reducing both manufacturing cost and device thickness while maintaining bending detection functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The manufacturing process is designed to produce multiple components simultaneously - the thin film transistor, display element, and bending sensor are all formed during the same manufacturing sequence. This multi-functionality approach allows a single manufacturing line to produce both the display device and its bending detection system without additional tooling or processes.

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

2Reliability

If a bending sensor is manufactured separately and attached to the flexible display device, then the bending detection function is achieved, but the device thickness increases

Engineering Contradiction:
Improvebending detection functionVSAvoiddevice thickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The bending sensor components (curved unit and detection unit) are merged into the same structural layer as the display device components. By forming all elements during a single manufacturing process, the sensor does not require additional attachment layers or interfaces that would increase overall device thickness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bending sensor structure is nested within the existing display device architecture. The curved unit and detection unit are positioned and formed within the same substrate and layer structure as the thin film transistor and display element, effectively hiding the sensor components within the overall device footprint without adding external thickness.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Ease of manufacture

If the bending sensor is integrated during the manufacturing process of the thin film transistor or display element, then the manufacturing cost is reduced and thickness is reduced, but the manufacturing process complexity increases

Engineering Contradiction:
Improvemanufacturing costVSAvoidmanufacturing process complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The manufacturing process is segmented into distinct sequential steps: forming the curved unit with specific patterns, depositing the detection unit material, and establishing electrical connections. This segmentation allows each sub-process to be optimized independently while maintaining overall integration, reducing the complexity burden that would result from attempting to form all components simultaneously in a single step.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The curved unit is formed in advance during the manufacturing process, creating a pre-prepared structure that receives the detection unit material. This preliminary action allows subsequent steps to proceed more simply, as the foundational sensor structure is already in place, reducing the complexity of later integration steps.

Inventive Principle:
Principle #10Preliminary 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

This approach allows for accurate detection of bending information without increasing the device's thickness or manufacturing costs, enabling the production of slim, flexible display devices that can maintain image quality even when bent.

Implementation Method 1

a curved unit disposed in the bezel area and in which an electric change occurs when the flexible substrate is bent

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentEP3037873B1Display device comprising bending sensor
Publication Date: 2019.09.25 LG DISPLAY CO LTD
  • EP3037873B1 patent drawingFigure 1
  • EP3037873B1 patent drawingFigure 2
  • EP3037873B1 patent drawingFigure 3

AI summary

A display device (100) including a bending sensor (120) is provided. A display device including a bending sensor (120) may include a flexible substrate (110) including a display area (DA) and a bezel area (ZA) surrounding the display area (DA); and the bending sensor (120) including a curved unit (121) disposed in the bezel area (ZA) and in which an electric change occurs when the flexible substrate (110) is bent, and a detection unit detecting bending information by sensing the electric change.