OLED Display Transmissive Film Destructive Interference

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Solution Overview

Problem

Conventional OLED displays suffer from reduced display characteristics due to external light reflection, which affects black representation and contrast.

Innovation Solution

The OLED display incorporates a transmissive film between two common electrodes, with light scattering spacer parts in the pixel defining layer that maintain a gap between the substrate and sealing member, and are formed using semi-transmissive metals like magnesium, silver, or aluminum, to suppress external light reflection through destructive interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional OLED displays use transparent electrodes and metal wires, then the display can be manufactured with standard processes, but external light reflection occurs which reduces display characteristics

Engineering Contradiction:
Improvemanufacturing processVSAvoidexternal light reflection
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of external light reflection into a beneficial effect by using the reflected light to interfere destructively with incoming external light. The metal wire and transparent electrode structure, which originally caused harmful reflection, is designed to create destructive interference that suppresses external light reflection and improves display characteristics.

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

Solution Approach 2:

The patent changes the optical parameters of the electrode structure by controlling the thickness, refractive index, and material composition of the transparent electrode and metal wire layers. By adjusting these parameters, the structure achieves destructive interference for external light while maintaining electrical functionality and manufacturability.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If a transmissive film is added between common electrodes to suppress external light reflection, then display characteristics improve, but device complexity increases

Engineering Contradiction:
Improveexternal light reflectionVSAvoidstructure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent makes the transparent electrode serve multiple functions: it provides electrical conductivity for the OLED operation and simultaneously acts as an optical interference layer to suppress external light reflection. This multi-functionality reduces the need for separate anti-reflection structures, thereby limiting the increase in device complexity.

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

Solution Approach 2:

The patent merges the electrical electrode function with the optical anti-reflection function into a single integrated structure. The transparent electrode and metal wire are designed to work together as both electrical conductors and optical interference elements, combining multiple functions into unified components.

Inventive Principle:
Principle #5Merging (Combining)

3Object-affected harmful factors

If light scattering spacer parts are used to maintain gap between substrate and sealing member, then external light reflection is suppressed, but manufacturing precision requirements increase

Engineering Contradiction:
Improveexternal light reflectionVSAvoidgap maintenance
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The light scattering spacer parts are designed to automatically maintain the gap between the substrate and sealing member through their own structural properties. The spacers self-align and self-position during assembly, using their geometric shape and light scattering characteristics to ensure proper gap maintenance without requiring high-precision external alignment processes.

Inventive Principle:
Principle #25Self-service

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 effectively reduces external light reflection, enhancing display properties such as contrast and image quality by minimizing light scattering and voltage drops between electrodes.

Implementation Method 1

suppress external light reflection through destructive interference

Methodology Applied
Scientific EffectDestructive interference: Interference

Implementation Method 2

light scattering spacer parts in the pixel defining layer

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP2207219B1Organic light emitting diode display and method of manufacturing the same
Publication Date: 2015.10.07 SAMSUNG DISPLAY CO LTD
  • EP2207219B1 patent drawingFigure 1
  • EP2207219B1 patent drawingFigure 2
  • EP2207219B1 patent drawingFigure 3

AI summary

An OLED display includes a substrate member (111), a plurality of pixel electrodes (710) on the substrate member (111), a pixel defining layer (190) on the substrate member, the pixel defining layer (190) including a pixel defining part (191) and a plurality of light scattering spacer parts (195), the pixel defining part (191) including a plurality of openings corresponding to and exposing the pixel electrodes (710), and the light scattering spacer parts (195) protruding upward from the pixel defining part (191) away from the substrate member (111), an organic light emitting layer (720) on the pixel electrodes (710), a first common electrode (730) on the organic light emitting layer (720), at least a portion of the first common electrode (730) being on the pixel defining layer (190) to overlap the light scattering spacer parts (195), a transmissive film (600) on the first common electrode (730), and a second common electrode (750) on the transmissive film (600).