Touch Unit Reflection Prevention for OLED Non-Display Areas

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Solution Overview

Problem

Existing organic light-emitting display devices face issues with light leakage due to external light reflection in the non-display areas, particularly caused by structures designed to prevent moisture transmission.

Innovation Solution

A display device design that includes a display panel with a substrate having a display area and a non-display area, an insulator with a valley portion along the outer side of the display area, and a touch unit with a reflection prevention unit that overlaps the valley portion to reduce external light reflectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If structures for preventing external moisture transmission are arranged in the non-display area, then moisture protection is improved, but external light reflection occurs causing light leakage

Engineering Contradiction:
Improvemoisture protectionVSAvoidexternal light reflection
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A black matrix layer is introduced as an intermediary substance between the moisture prevention structure and the external environment. This black matrix layer specifically absorbs or blocks external light in the non-display area, preventing light reflection and leakage while allowing the underlying moisture prevention structures to maintain their protective function. The black matrix acts as a mediator that addresses the optical issue without interfering with the moisture protection mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The black matrix layer is selectively applied only in the non-display area where moisture prevention structures are present and light reflection is problematic. This localized application ensures that the moisture protection function is maintained across the entire device while light reflection is specifically addressed only where needed, optimizing both functions without unnecessary material usage elsewhere.

Inventive Principle:
Principle #3Local quality

2Reliability

If the non-display area structures are added for moisture prevention, then device reliability is improved, but display quality deteriorates due to light leakage

Engineering Contradiction:
Improvedevice reliabilityVSAvoiddisplay quality
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The black matrix layer serves as an intermediary that decouples the moisture prevention function from the optical performance issue. It allows the moisture prevention structures to remain intact for reliability while independently addressing the light leakage problem that affects display quality, thereby resolving the contradiction between device reliability and display quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If moisture prevention structures are formed along substrate edges, then encapsulation effectiveness is improved, but external light is reflected causing defects

Engineering Contradiction:
Improveencapsulation effectivenessVSAvoidlight reflection defects
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The black matrix layer is positioned as an intermediary over the edge-aligned moisture prevention structures. It specifically targets and eliminates the harmful light reflection effect generated by these structures, while allowing the structures themselves to maintain their encapsulation effectiveness for moisture prevention.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The proposed design effectively minimizes light leakage by reducing external light reflection in the non-display areas, thereby enhancing the overall display quality and reducing defects.

Implementation Method 1

a reflection prevention unit that overlaps the valley portion and is configured to reduce reflectivity of external light

Methodology Applied
Scientific EffectLight reflection prevention: Absorption (EM radiation)

Data Source

PatentEP3680756B1Display device with a touch unit having external light reflection prevention unit
Publication Date: 2025.06.04 SAMSUNG DISPLAY CO LTD
  • EP3680756B1 patent drawingFigure 1~2
  • EP3680756B1 patent drawingFigure 3
  • EP3680756B1 patent drawingFigure 4~5

AI summary

Provided is a display device in which a defect by external light reflection is minimized in a non-display area. The display device includes a display panel and a touch unit arranged on the display panel. The display panel may include: a substrate including a display area and a non-display area arranged around the display area; an insulator including a valley portion, the valley portion being defined as an opening arranged along an outer side of the display area in the non-display area; and a display unit arranged in the display area and including a light-emitting element electrically connected to a thin film transistor. The touch unit may include a reflection prevention unit that overlaps the valley portion and is configured to reduce reflectivity of external light.