Organic Light Emitting Device Microcavity Viewing Angle Chromaticity
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Solution Overview
Problem
Top emission system light emitting devices face challenges in achieving both good feed performance and good viewing angle characteristics of chromaticity, especially as device size increases, due to worsening viewing angle dependency of chromaticity.
Innovation Solution
A light emitting device with a microcavity structure comprising a first reflective interface on the organic light emitting layer side of the first reflective layer, a second reflective interface on the organic light emitting layer side of the first metal layer, and a third reflective interface on the organic light emitting layer side of the second metal layer, where the second reflective layer includes a first metal layer, a transparent layer, and a second metal layer in this order from the organic light emitting layer side, which helps in restraining the worsening of viewing angle dependency of chromaticity even when the first metal layer's film thickness is enlarged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the first metal layer's film thickness is enlarged to improve feed performance, then light extraction efficiency is improved, but viewing angle dependency of chromaticity worsens
Solution Approach 1:
The second reflective layer is segmented into multiple sub-layers including a first metal layer, a transparent layer, and a second metal layer. This segmentation allows each sub-layer to contribute differently to light extraction, enabling the first metal layer to be thick enough for good feed performance while the transparent and second metal layers compensate to maintain viewing angle characteristics.
Solution Approach 2:
The second reflective layer uses a composite structure combining metal layers with a transparent layer. This composite material approach allows the layer to simultaneously achieve high reflectivity (from metal layers) and control over light phase and direction (from the transparent layer), resolving the contradiction between extraction efficiency and viewing angle dependency.
2Area of stationary object
If the device size is enlarged, then display area is increased, but both feed performance and viewing angle characteristic of chromaticity become difficult to realize
Solution Approach 1:
The invention addresses the size scaling problem by optimizing the microcavity structure in the vertical dimension rather than relying on lateral dimensions. By controlling the optical path length and phase relationships through the layered structure thicknesses, the device maintains consistent optical performance whether small or large in area.
3Area of stationary object
If the device size is enlarged, then display area is increased, but viewing angle characteristic of chromaticity deteriorates
Solution Approach 1:
The second reflective layer is segmented into multiple sub-layers including a first metal layer, a transparent layer, and a second metal layer. This segmentation allows each sub-layer to contribute differently to light extraction, enabling the first metal layer to be thick enough for good feed performance while the transparent and second metal layers compensate to maintain viewing angle characteristics.
Solution Approach 2:
The invention optimizes specific parameters of the microcavity structure, including the thicknesses of the transparent layer and metal layers, and the optical path length between reflective interfaces. By carefully controlling these parameters, the device achieves size-independent viewing angle characteristics through constructive and destructive interference effects.
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 solution ensures both good feed performance and viewing angle characteristics of chromaticity are secured, enhancing light distribution characteristics and reducing angle dependencies of luminance and chromaticity, making it suitable for high-image-quality display devices.
Implementation Method 1
a light emitting device using organic electroluminescent sections that emit light by an organic electroluminescence (EL) phenomenon
Implementation Method 2
a first reflective interface on the organic light emitting layer side of the first reflective layer, a second reflective interface on the organic light emitting layer side of the first metal layer, and a third reflective interface on the organic light emitting layer side of the second metal layer
Implementation Method 3
A microcavity structure is formed by a structure including a first reflective interface on the organic light emitting layer side of the first reflective layer, a second reflective interface on the organic light emitting layer side of the first metal layer, and a third reflective interface on the organic light emitting layer side of the second metal layer
Data Source
AI summary
Disclosed is a light emitting device including a plurality of organic electroluminescent sections each including a first reflective layer, an organic light emitting layer and a second reflective layer in this order, and a light extraction surface from which light emitted from each of the organic electroluminescent sections through the second reflective layer is extracted. The second reflective layer includes a first metal layer, a transparent layer and a second metal layer in this order from the organic light emitting layer side, and in each of the organic electroluminescent sections, a microcavity structure is formed by a structure that includes a first reflective interface on the organic light emitting layer side of the first reflective layer, a second reflective interface on the organic light emitting layer side of the first metal layer, and a third reflective interface on the organic light emitting layer side of the second metal layer.