Organic EL Element with Reflection Filter for Flexible Optical Layouts

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Solution Overview

Problem

Existing light emitting elements, such as those using light transmission filters, face limitations in achieving various optical layouts while narrowing spectral width due to fixed light emission directions, which restricts their application in living body sensing and other measurement applications.

Innovation Solution

An organic electroluminescent element with a light emitting layer, a light shielding electrode, a light transmitting electrode, and a reflection filter that selectively reflects light components, allowing for adjustable light emission directions and spectral narrowing, enabling flexible optical layouts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a light transmission filter is used to narrow the spectral width, then the spectral width is narrowed, but the light emission direction is uniquely limited

Engineering Contradiction:

Improvespectral widthVSAvoidoptical layout flexibility

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

Instead of using a light transmission filter that transmits only specific wavelengths (which limits emission direction), the invention uses a light reflection filter that reflects specific wavelengths. This inversion of the filtering approach (from transmission to reflection) allows the filter to be positioned at an angle to the light emitting layer, enabling flexible optical layouts while maintaining spectral narrowing functionality.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention introduces a spatial dimension by positioning the light reflection filter at an angle relative to the light emitting layer, rather than having the filter co-planar with the emitting layer. This angular arrangement in a different dimensional orientation allows light to be reflected at specific angles, providing flexibility in optical layout design while maintaining spectral selectivity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If the light emission direction is fixed by the element structure, then the spectral width can be narrowed, but various optical layouts cannot be achieved

Engineering Contradiction:

Improvespectral widthVSAvoidoptical layout configuration

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The invention makes the optical system dynamic by allowing the light reflection filter to be positioned at different angles relative to the light emitting layer. This dynamic angular positioning capability enables the system to adapt to various optical layout requirements while maintaining the spectral narrowing function, rather than being fixed in a single configuration.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention separates the spectral filtering function from the light emission function by using a dedicated light reflection filter component positioned at an angle. This segmentation allows the filter to be independently positioned and angled to achieve desired optical layouts, while the light emitting layer maintains its spectral characteristics.

Inventive Principle:

Principle #1Segmentation

3Manufacturing precision

If a light transmission filter is used, then the spectral width is narrowed, but the device complexity increases due to fixed emission direction constraints

Engineering Contradiction:

Improvespectral widthVSAvoidoptical layout constraints

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The light reflection filter serves multiple functions: it narrows the spectral width by selectively reflecting specific wavelengths and simultaneously enables flexible optical layouts by being positionable at different angles. This multi-functionality reduces the need for additional components or complex configurations, thereby reducing overall device complexity while achieving both spectral narrowing and layout flexibility.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

The organic electroluminescent element achieves various optical layouts while maintaining spectral narrowing, enhancing light utilization efficiency and emission intensity, suitable for applications like living body sensing and measurement apparatuses.

Implementation Method 1

a reflection filter arranged on a side opposite to the light emitting layer with respect to the second electrode and selectively reflecting light from the light emitting layer

Methodology Applied

Scientific EffectSelective reflection: Reflection

Implementation Method 2

a light emitting layer containing an organic light emitting material

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS11258047B2Organic electroluminescent element and measurement apparatus

Publication Date: 2022.02.22 HAMAMATSU PHOTONICS KK

AI summary

An organic EL element 100 includes a light emitting layer 110 containing an organic light emitting material, a light shielding electrode 120 being arranged on one surface 110a side of the light emitting layer 110, a light transmissive electrode 130 being arranged on the other surface 110b side of the light emitting layer 110, a reflection filter 160 being arranged on a side opposite to the light emitting layer 110 with respect to the light transmissive electrode 130 and selectively reflecting a light L1 from the light emitting layer 110.