Organic Light Emitting Display Device with Bidirectional Emissive Areas

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Solution Overview

Problem

Existing organic light emitting display devices with a mirror function suffer from reduced light transmittance and color reproduction due to the presence of a polarizer, and are unable to achieve bidirectional image display.

Innovation Solution

The design includes a display panel with a first emissive area and a reflective area, where the first emissive area emits light in one direction and the reflective area reflects light, while also emitting light in an opposite direction through a second emissive area, allowing for bidirectional light emission without additional deposition processes, thus enhancing light transmittance and color reproduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a polarizer is attached on the encapsulation substrate to prevent dazzle, then the mirror function is improved, but light transmittance and color reproduction rate are reduced

Engineering Contradiction:
Improvedazzle preventionVSAvoidlight transmittance
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The patent removes the polarizer from the display structure entirely. Instead of using a polarizer to control glare, the invention uses the reflective part itself to perform both mirror and display functions, extracting the unnecessary polarizer component that was degrading light transmittance and color reproduction.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The reflective part is designed to serve multiple functions: it acts as a mirror reflector during non-driving periods and as an emissive display area during driving periods. This multi-functionality eliminates the need for separate polarizer components, maintaining high light transmittance while preventing dazzle through controlled reflection and emission.

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

2Object-affected harmful factors

If a polarizer is attached on the encapsulation substrate to prevent dazzle, then the mirror function is improved, but color reproduction rate is reduced

Engineering Contradiction:
Improvedazzle preventionVSAvoidcolor reproduction rate
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The patent removes the polarizer component that was causing color reproduction degradation. By using the reflective part to directly emit light in bidirectional mode, the system eliminates the polarizer's negative impact on color accuracy while maintaining dazzle prevention through controlled light emission and reflection.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the operational parameters of the reflective part by applying driving signals to enable bidirectional light emission. This parameter change allows the reflective part to transition from passive reflection to active emission, improving color reproduction by eliminating the polarizer's filtering effect while maintaining glare control through directional emission.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the reflective part is used only for mirror function without pixel circuit, then manufacturing complexity is reduced, but bidirectional image display capability is lost

Engineering Contradiction:
Improvepixel circuit structureVSAvoidbidirectional image display capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The reflective part is designed as a multi-functional element that can operate in mirror mode during non-driving periods and display mode during driving periods. By integrating pixel circuits into the reflective part, the system achieves bidirectional image display capability while maintaining manufacturing efficiency through shared structural elements between mirror and display functions.

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

Solution Approach 2:

The reflective part transitions dynamically between mirror and display functions based on driving signals. During non-driving periods, it reflects light for mirror functionality; during driving periods, pixel circuits activate to enable bidirectional light emission for image display. This dynamic switching capability provides versatility without requiring permanently complex structures.

Inventive Principle:
Principle #15Dynamics

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 configuration enhances light transmittance and color reproduction rates while enabling bidirectional image display without damaging the organic material, achieving high luminance with low power consumption.

Implementation Method 1

a first organic light emitting device provided on the first emissive area to emit light in response to application of a driving signal, a second organic light emitting device provided on the second emissive area to emit light in response to application of the driving signal

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

a reflective area overlapping the reflective part of each pixel and emits light in the first surface direction parallel to a surface of the substrate when light is incident on the substrate in the second surface direction opposite to the first surface direction

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3343628B1Organic light emitting display device and method of manufacturing thereof
Publication Date: 2023.01.04 LG DISPLAY CO LTD
  • EP3343628B1 patent drawingFigure 1~2
  • EP3343628B1 patent drawingFigure 3
  • EP3343628B1 patent drawingFigure 4A

AI summary

Disclosed is an organic light emitting display device. The organic light emitting display device including a plurality of pixels provided on a substrate. The plurality of pixels each include a first emissive area emitting light in a first surface direction of the substrate, a reflective area reflecting incident light in the first surface direction of the substrate, and a second emissive area overlapping the reflective area and emitting light in a second surface direction opposite to the first surface direction of the substrate. The organic light emitting display device may further include an auxiliary color filter provided in the first emissive area. In the organic light emitting display device, since a polarizer is replaced with a color filter, a light transmittance and a color reproduction rate are enhanced, and bidirectional image display is realized through the second emissive area.