OLED Display Functional Layer Constructive Interference

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Solution Overview

Problem

Conventional organic light emitting diode displays suffer from reduced image visibility due to external light reflection, particularly when one of the electrodes is light reflective, and the use of polarizing plates to mitigate this issue lowers luminous efficiency and increases thickness.

Innovation Solution

The implementation of a functional layer with a first semi-transmissive layer, a transmissive layer, and a second semi-transmissive layer, where the first electrode is light transmissive and the second electrode is light reflective, to create constructive interference of external light, reducing reflection and eliminating the need for a polarizing plate, thereby enhancing luminous efficiency and maintaining a thinner display.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a polarizing plate is attached to the surface of the substrate to reduce external light reflection, then image visibility is improved, but luminous efficiency is lowered and thickness is increased

Engineering Contradiction:

Improveexternal light reflectionVSAvoidluminous efficiency

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent introduces a functional layer as an intermediary component between the substrate and the organic light emitting diode. This functional layer includes a first semi-transmissive layer, a transmissive layer, and a second semi-transmissive layer that work together to reduce external light reflection through constructive interference, replacing the need for a polarizing plate and thereby preserving luminous efficiency

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the optical parameters of the functional layer components, specifically controlling the thickness and refractive index of the first semi-transmissive layer, transmissive layer, and second semi-transmissive layer to achieve constructive interference of external light, thereby reducing reflection without the energy loss associated with polarizing plates

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If a polarizing plate is attached to the surface of the substrate to reduce external light reflection, then image visibility is improved, but thickness is increased

Engineering Contradiction:

Improveexternal light reflectionVSAvoidthickness

Core Design Contradiction:

Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies local quality by making each layer of the functional layer have specific optical properties (semi-transmissive or transmissive) tailored to its position and function within the overall structure, enabling the system to achieve anti-reflection functionality without adding significant thickness

Inventive Principle:

Principle #3Local quality

3Illumination intensity

If a light reflective electrode is used, then electrode reflectivity is improved, but external light reflection increases and image visibility is lowered

Engineering Contradiction:

Improveelectrode reflectivityVSAvoidexternal light reflection

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of external light reflection from the light reflective electrode into a beneficial effect by designing the functional layer to create constructive interference with the reflected light. The functional layer's specific thickness and refractive index cause external light to interfere constructively with itself, reducing overall reflection and improving image visibility while maintaining the electrode's high reflectivity for emitted light

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 significantly reduces external light reflection, improves luminous efficiency, and maintains a compact thickness by utilizing constructive interference to suppress external light reflection and enhance light emission from the organic emission layer.

Implementation Method 1

configured to produce constructive interference of lights transmitted from the outside

Methodology Applied

Scientific EffectConstructive interference: Interference

Data Source

PatentUS8334650B2Organic light emitting diode display

Publication Date: 2012.12.18 SAMSUNG DISPLAY CO LTD

AI summary

An organic light emitting diode display device is disclosed. The device includes: a substrate; a functional layer positioned on the substrate and making constructive interference of transmitted lights; a first electrode positioned on the functional layer; an organic emission layer positioned on the first electrode; and a second electrode positioned on the organic emission layer.