Organic Light Emitting Display Mirror Function via Reflective Layer

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Solution Overview

Problem

Existing organic light emitting displays lack a efficient solution for transitioning between image display and mirror functions while maintaining structural simplicity and productivity.

Innovation Solution

The implementation of a mirror-type organic light emitting display with a light-shielding reflective layer on a substrate, which reflects external light when the display is not in use, and includes a pixel circuit with thin film transistors and a storage capacitor to manage light emission and reflection, along with a flexible printed circuit board for voltage supply, allowing for both image display and mirror functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a light-shielding reflective layer is added to enable mirror function, then the display can function as both image display and mirror, but the device complexity increases

Engineering Contradiction:
Improvedual function (image display and mirror)VSAvoidstructure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The light-shielding reflective layer serves dual purposes: it acts as a reflective surface for mirror mode and as a light-shielding layer to prevent external light from reaching the transistor active layers. This multi-functional design enables the display to switch between image display and mirror functions without requiring separate components for each function.

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

Solution Approach 2:

The patent combines the light-shielding function and the reflective function into a single integrated layer structure. The reflective layer is positioned to simultaneously block external light from reaching sensitive areas and reflect ambient light for mirror functionality, merging what could be separate functions into one cohesive structural element.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If additional layers and components are added for mirror functionality, then mirror function is achieved, but manufacturing complexity and productivity decrease

Engineering Contradiction:
Improvemirror functionVSAvoidmanufacturing efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The light-shielding reflective layer is integrated into the existing display stack during the same manufacturing process, combining the formation of the reflective layer with the light-shielding function in a single fabrication step. This approach avoids the need for separate manufacturing processes for adding mirror functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The same layer structure serves multiple functions (light-shielding and reflection), meaning that a single manufacturing process achieves what would otherwise require multiple separate processes, thereby maintaining productivity while enabling dual functionality.

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

3Object-affected harmful factors

If the reflective layer is positioned to overlap transistor active layers, then external light is blocked, but the device complexity increases due to additional buffer films and connections

Engineering Contradiction:
Improveexternal light interferenceVSAvoidbuffer film and connection structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The buffer film positioned between the reflective layer and transistor active layers serves dual purposes: it provides electrical isolation to prevent short circuits while also allowing the reflective layer to maintain its light-shielding function. This multi-functional element reduces the need for additional complex isolation structures.

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

Solution Approach 2:

The buffer film acts as an intermediary layer that mediates between the reflective layer and the transistor active layers, providing necessary electrical isolation while maintaining the light-shielding effectiveness of the reflective layer. This intermediary structure simplifies the overall design compared to more complex isolation schemes.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of manufacture

If the display uses a simple structure without additional reflective layers, then manufacturing is simpler, but it cannot function as a mirror

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmirror function
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The light-shielding reflective layer is designed to perform both light-shielding and mirror reflection functions simultaneously. By positioning this layer to overlap with non-emission areas and route connections properly, the same basic structure enables dual functionality without requiring entirely separate manufacturing processes for mirror capability.

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

Solution Approach 2:

The display can switch between image display mode and mirror mode by controlling the light emitting device state. In mirror mode, the light emitting device is turned off or set to a dark state, allowing the reflective layer to reflect ambient light effectively, while in image display mode, the light emitting device is activated. This parameter change (light emission state) enables functional switching without structural changes.

Inventive Principle:
Principle #35Parameter changes

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

Enables stable operation as both an image display and a mirror without requiring additional reflective layers or polarizing plates, simplifying the structure and manufacturing process, and improving productivity.

Implementation Method 1

a light-shielding reflective layer on the substrate overlapping a non-emission area of the substrate to reflect external light incident through the substrate

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a light emitting device disposed in an emission area of a substrate. The light emitting device emits internal light through the emission area of the substrate

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3331022B1Organic light emitting display
Publication Date: 2021.07.14 LG DISPLAY CO LTD
  • EP3331022B1 patent drawingFigure 1
  • EP3331022B1 patent drawingFigure 2
  • EP3331022B1 patent drawingFigure 3A

AI summary

Disclosed is an organic light emitting display having a mirror function. In an embodiment, a light-shielding reflective layer overlaps areas of the organic light emitting display except for emission areas provided with light emitting devices formed therein. The light-shielding reflective layer prevents light from entering channel regions of active layers and reflects external light, for example, when the organic light emitting device is not operated to display an image, and thus the organic light emitting display may stably implement a mirror function.