Transparent OLED Light Absorption via Black Bank and Shielding Layer

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Solution Overview

Problem

Transparent organic light-emitting display devices struggle to prevent external light reflection, which deteriorates image quality due to the absence of a polarizing plate.

Innovation Solution

The implementation of a black bank between the transmission and light emission areas to absorb external light, combined with a shielding layer made of transparent conductive material to minimize reflection and enhance transmittance, while maintaining the transparency of the display.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a polarizing plate is used to reduce external light reflection, then image quality is improved, but transparency is lost

Engineering Contradiction:
Improveexternal light reflectionVSAvoidtransparency
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The display device is divided into distinct functional areas: a light emission area for displaying images and a transmission area for maintaining transparency. This segmentation allows different optical characteristics in different regions, enabling the device to reduce reflection in the transmission area without compromising overall transparency

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the display device are given different optical properties. The transmission area is designed with specific reflective characteristics to reduce external light reflection, while the light emission area maintains its imaging function. This local differentiation resolves the contradiction by applying reflection reduction only where needed

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If no polarizing plate is used to maintain transparency, then transparency is improved, but external light reflection increases

Engineering Contradiction:
ImprovetransparencyVSAvoidexternal light reflection
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The polarizing plate, which causes the contradiction between transparency and reflection reduction, is extracted or removed from the device structure. Instead, a more selective approach is implemented where only the transmission area has reflection reduction properties, allowing the device to achieve both transparency and reflection reduction without the polarizing plate

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

An intermediate structure or layer is introduced in the transmission area that mediates between the need for transparency and the need to reduce reflection. This intermediary element allows light transmission while simultaneously reducing external light reflection, resolving the contradiction without requiring a polarizing plate

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

This solution effectively reduces external light reflection, improving image quality and transparency in transparent organic light-emitting display devices without the need for a polarizing plate.

Implementation Method 1

a black bank located between the transmission area and the light emission area so as to cover the edge of the first electrode

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a shielding layer located to cover a region of the planarization film corresponding to the transmission area and the side surface of the planarization film

Methodology Applied
Scientific EffectLight transmission: Refraction

Data Source

PatentEP3343634B1Organic light-emitting display device
Publication Date: 2020.05.20 LG DISPLAY CO LTD
  • EP3343634B1 patent drawingFigure 1
  • EP3343634B1 patent drawingFigure 2
  • EP3343634B1 patent drawingFigure 3A~3B

AI summary

Disclosed is an organic light-emitting display device that is capable of preventing the reflection of light incident from outside and improving transparency when a transparent display is realized. The organic light-emitting display device includes a first substrate (10) defined by a transmission area (T/A) and a light emission area (E/A), a first electrode (51) located on a region of a planarization film (14), which covers a thin film transistor (T), corresponding to the light emission area (E/A), the first electrode (51) being electrically connected to the thin film transistor (T), and a shielding layer (56) located to cover a region of the planarization film (14) corresponding to the transmission area (T/A) and the side surface of the planarization film (14), the shielding layer (56) being electrically isolated from the first electrode (51). A black bank (15) is provided between the transmission area (T/A) and the emission area (E/A) so as to cover the edge of the first electrode (51), and an organic light emissive layer (52) and a second electrode (53), which covers the organic light emissive layer (52), are sequentially formed on the first electrode (51).