Overlapping OLED Emissive Layers for Simplified Masking

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional image displaying systems using organic light-emitting devices (OLEDs) face manufacturing complexities and reduced lighting efficiency due to the need for multiple metal masks and color filters, which can lead to decreased yields and shortened OLED lifetime.

Innovation Solution

An image displaying system with a reduced number of metal masks and color filters, where two organic light-emitting layers overlap within three OLEDs, allowing for simplified manufacturing and increased mask opening size, thereby enhancing yield and efficiency, and using a single color filter within one OLED to improve lighting efficiency and extend OLED lifetime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If three separate color filters are used to filter white light into red, blue and green light, then full-color displaying effect can be achieved, but manufacturing processes become complicated and lighting efficiency is reduced

Engineering Contradiction:

Improvelighting efficiencyVSAvoidmanufacturing process complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the need for three separate color filters by using three OLEDs with different organic light-emitting layers that directly emit red, blue, and green light. This removes the filtering step entirely, simplifying the manufacturing process and eliminating light absorption losses associated with filters.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using white light and filtering it to obtain colors (conventional approach), the invention inverts the approach by directly generating the three primary colors through three separate OLEDs with specific organic light-emitting layers, then mixing them to form white light for display.

Inventive Principle:

Principle #13The other way round (Inversion)

2Illumination intensity

If light intensity is increased to compensate for filter absorption, then display brightness can be maintained, but current through OLEDs must be increased, shortening OLED lifetime

Engineering Contradiction:

Improvedisplay brightnessVSAvoidOLED lifetime

Core Design Contradiction:

Illumination intensityVSDuration of action of stationary object

Solution Approach 1:

The invention converts the potential harm of filter absorption into a benefit by eliminating the filters entirely. The organic light-emitting layers are designed to directly emit the required colors with high efficiency, so no compensation through increased current is needed, thus preserving OLED lifetime while maintaining display brightness.

Inventive Principle:

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

3Ease of manufacture

If only one metal mask is used during OLED manufacturing, then manufacturing is simplified, but mask alignment precision must be very high to maintain yield

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidmask alignment precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention segments the manufacturing process into three separate OLED fabrication lines, each producing OLEDs with a specific organic light-emitting layer for one primary color. This segmentation allows each metal mask to be optimized for a single color pattern, reducing the complexity of aligning multiple masks and maintaining high yield through simplified precision requirements.

Inventive Principle:

Principle #1Segmentation

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 approach reduces manufacturing costs and time, increases OLED yield and efficiency, and extends the lifetime of the image displaying system by simplifying the manufacturing process and enhancing lighting efficiency.

Implementation Method 1

The electrons and the holes are respectively ejected from the electron transporting layer and the hole transporting layer and are recombined in the organic light-emitting layer so that the organic light-emitting layer emits light.

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

the white light is filtered to form the red light, the blue light and the green light

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS7659664B2System for displaying image

Publication Date: 2010.02.09 RED OAK INNOVATIONS LTD

AI summary

A system for displaying an image includes a plurality of pixels each having a first organic light-emitting device (OLED), a second OLED and a third OLED. The pixel includes a first electrode layer, a first organic light-emitting layer, a second organic light-emitting layer, a second electrode layer and a color filter. The first organic light-emitting layer is disposed on the first electrode layer and within the first OLED and the second OLED. The second organic light-emitting layer is disposed on the first electrode layer and within the second OLED and the third OLED so that the first and second organic light-emitting layers overlap within the second OLED. The second electrode layer is disposed on the first organic light-emitting layer and the second organic light-emitting layer. The color filter is disposed within the second OLED.