Digitizer Layer Placement for Foldable Display Reliability

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Solution Overview

Problem

Bendable or foldable display devices face reliability issues due to cracks in the digitizer layer when repeatedly bent or folded, leading to deteriorated touch input precision and device reliability.

Innovation Solution

A display apparatus with a digitizer layer positioned outside the bendable or foldable area, using a touch sensor layer and electromagnetic sensor driver to detect touch inputs, and a main processor to correct coordinate data from overlapping sensing areas, ensuring accurate touch input detection without damaging the digitizer layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the digitizer layer is located in the display area and repeatedly bent or folded, then the display device can achieve bendable or foldable functionality, but cracks are generated and reliability deteriorates

Engineering Contradiction:
Improvebendable or foldable functionalityVSAvoiddevice reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent divides the display area into a non-bendable first display area containing the digitizer layer and a bendable second display area. This segmentation isolates the digitizer layer from the bending stress, allowing the display device to achieve foldable functionality while protecting the digitizer layer from cracks.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the digitizer layer from the bendable region and positions it in the non-bendable first display area. By taking out the digitizer layer from the folding area, the patent eliminates the source of cracking while preserving touch input functionality through the touch sensor layer in the second display area.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If the digitizer layer is positioned outside the bendable area, then reliability is improved, but touch input detection in the folding area becomes challenging

Engineering Contradiction:
Improvedigitizer layer reliabilityVSAvoidtouch input detection accuracy
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent implements multi-functionality by having the touch sensor layer serve dual purposes: detecting touch inputs in the non-bendable first display area and detecting touch inputs in the bendable second display area. This universal touch detection mechanism ensures accurate touch input detection across the entire display area while maintaining the digitizer layer in the safe non-bendable region.

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

Solution Approach 2:

The patent introduces the touch sensor layer as an intermediary between the user's touch input and the display area. The touch sensor layer detects touch inputs in the bendable second display area and transmits this information to the main processor, which then determines the touch coordinates without requiring the digitizer layer to be in the bending area.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If the touch sensor layer is added to detect touch inputs in the bendable area, then touch sensitivity is enhanced, but device complexity increases

Engineering Contradiction:
Improvetouch input precisionVSAvoidlayer structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the touch detection functionality into the existing display panel structure by integrating the touch sensor layer with the display layer. This combination allows the touch sensor layer to detect inputs in the bendable area without adding a separate, complex digitizer layer structure, thus enhancing touch sensitivity while minimizing increased device complexity.

Inventive Principle:
Principle #5Merging (Combining)

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

Enhances touch sensitivity and reliability in folding areas by synchronizing touch coordinate data, reducing stress on the digitizer layer and preventing cracks, thus improving the overall durability and precision of touch input detection.

Implementation Method 1

an electromagnetic sensor driver driving the first electrode patterns and the second electrode patterns of the digitizer layer to form a magnetic field in the digitizer layer

Methodology Applied
Scientific EffectElectromagnetic field generation: Electromagnetic Induction

Data Source

PatentEP4016261A1Display apparatus
Publication Date: 2022.06.22 SAMSUNG DISPLAY CO LTD
  • EP4016261A1 patent drawingFigure 1
  • EP4016261A1 patent drawingFigure 2
  • EP4016261A1 patent drawingFigure 3

AI summary

A display device includes: a display panel comprising a display layer having a first display area, a second display area spaced apart from the first display area, and a third display area between the first and second display areas, and a touch sensor layer having a plurality of touch electrodes in the first, second, and third display areas on the display layer; a touch driver configured to drive the touch electrodes of the touch sensor layer; a digitizer layer below the display panel and overlapping with the first and second display areas, the digitizer layer comprising first electrode patterns and second electrode patterns; and an electromagnetic sensor driver configured to drive the first electrode patterns and the second electrode patterns of the digitizer layer to form a magnetic field in the digitizer layer.