Flexible Touch Screen Panel Polarizing Layer Design

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Solution Overview

Problem

Existing touch screen panels, especially capacitive ones, face challenges in achieving flexibility and thinness while maintaining high visibility and efficiency, as they require thick polarizing plates with rigid support layers that hinder bendability and increase manufacturing complexity.

Innovation Solution

A flexible touch screen panel is designed with a polarizing functional layer directly attached to a flexible window substrate, eliminating the rigid support layer and integrating sensing patterns on a retardation compensation film, using transparent adhesives and polymers like PMMA and PVA, and optimizing the angle between the polarizer's absorption axis and the touch screen panel's bending axis for enhanced mechanical bendability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid support layer is used in the polarizing plate to maintain structural integrity, then the polarizing plate provides sufficient mechanical strength, but the touch screen panel loses flexibility and increases in thickness

Engineering Contradiction:
Improvemechanical strengthVSAvoidflexibility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The invention extracts and removes the rigid support layer from the polarizing plate structure, retaining only the essential polarizing film and compensation film layers. This elimination of the support layer directly resolves the contradiction by providing flexibility while maintaining the core optical functions through the remaining thin-film structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the rigid support layer with flexible thin-film structures, specifically using a polarizing film and compensation film that can be laminated directly onto the substrate. This approach provides the necessary mechanical strength through the film lamination while enabling flexibility and reducing thickness.

Inventive Principle:
Principle #30Flexible shells and thin films

2Stability of the object's composition

If a rigid support layer is included in the polarizing plate, then manufacturing stability is maintained, but the number of manufacturing steps increases and complexity rises

Engineering Contradiction:
Improvemanufacturing stabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The invention merges the functions of the support layer, polarizing film, and compensation film into an integrated thin-film structure. By combining these layers and eliminating the separate support layer, the manufacturing process is simplified while maintaining stability through direct lamination onto the substrate.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a thick polarizing plate with support layer is used, then optical performance is maintained, but the overall thickness of the touch screen panel increases

Engineering Contradiction:
Improveoptical performanceVSAvoidthickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The invention extracts and removes the thick support layer from the polarizing plate, retaining only the essential thin-film layers needed for optical performance. This extraction maintains the polarizing and compensating optical functions while dramatically reducing the overall thickness.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses flexible thin-film structures for the polarizing and compensation functions, replacing the thick rigid support layer. This approach maintains optical performance through proper film selection and lamination while enabling thin-profile construction.

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 design reduces the touch screen panel's thickness by about 80µm, ensures flexibility, improves image visibility, and minimizes manufacturing costs and complexity by integrating the polarizer and retardation compensation film directly onto the substrate, while maintaining high mechanical bendability and image quality.

Implementation Method 1

The polarizer may be implemented by stretching a polymer film, and has an absorption axis in the stretched direction

Methodology Applied
Scientific EffectPolarisation: Polarisation

Implementation Method 2

The polarizer may be attached on the first surface of the window substrate through a first transparent adhesive layer, and the retardation compensation film may be attached on a first surface of the polarizer through a second transparent adhesive layer

Methodology Applied
Scientific EffectAdhesive: Adhesive

Data Source

PatentEP2829957B1Flexible touch screen panel and flexible display device with the same
Publication Date: 2018.12.26 SAMSUNG DISPLAY CO LTD
  • EP2829957B1 patent drawingFigure 1
  • EP2829957B1 patent drawingFigure 2~3
  • EP2829957B1 patent drawingFigure 4

AI summary

A flexible touch screen panel includes a window substrate (10), a polarizing functional layer (30), sensing patterns (220) and sensing lines (230). The window substrate (10) has flexibility. The polarizing functional layer (30) is attached on a first surface of the window substrate (10), and is divided into an active area and a non-active area positioned at the outside of the active area. The sensing patterns (220) are formed in the active area on a first surface of the polarizing functional layer (30). The sensing lines (230) are formed in the non-active area on the first surface of the polarizing functional layer (30), and are connected to the sensing patterns (220). In the touch screen panel, the polarizing functional layer (30) has a laminated structure of a polarizer (12) and a retardation compensation film (16), which are attached on the first surface of the window substrate (10).