Microresonator Light Emitting Device with Segmented Optical Paths
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic light emitting devices with microresonator structures face challenges in enhancing color purity and light extraction efficiency, as the resonance effect narrows spectral line width, reducing luminance and lowering color purity when using optical members like microlenses.
Innovation Solution
A light emitting device with a resonator structure comprising a reflective film, a first electrode, an organic film with a light emitting layer, and a second electrode, where the reflective film's upper surface is flatter than the first electrode, and the resonator structure has multiple optical path lengths, allowing for efficient extraction of desired wavelengths without compromising color purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a microresonator structure is used to improve color purity, then color purity is improved, but the spectral line width narrows and the amount of extracted light decreases
Solution Approach 1:
The resonator structure is divided into multiple regions with different optical path lengths. The first region has a first optical path length optimized for color purity, while the second region has a second optical path length optimized for light extraction efficiency. This segmentation allows each region to contribute differently to the overall performance, resolving the contradiction between color purity and light amount.
Solution Approach 2:
Different regions of the resonator structure are assigned different optical path lengths tailored to their specific functions. The central region (first region) has optical path length optimized for resonance and color purity, while the peripheral region (second region) has optical path length optimized for extracting oblique light. This local differentiation of optical properties enables simultaneous achievement of high color purity and high light extraction efficiency.
2Illumination intensity
If an optical member such as a microlens is used to improve luminance, then luminance is improved, but oblique light deviating from the normal direction is extracted and color purity lowers
Solution Approach 1:
The optical member is divided into a first optical member corresponding to the first region and a second optical member corresponding to the second region. The first optical member has optical characteristics optimized for normal direction light transmission to maintain color purity, while the second optical member has optical characteristics optimized for oblique light extraction to improve luminance. This segmentation resolves the contradiction between luminance enhancement and color purity maintenance.
3Ease of manufacture
If the resonator structure has uniform optical path length, then manufacturing is simplified, but light extraction efficiency is reduced
Solution Approach 1:
Instead of using a uniform optical path length throughout the resonator structure, the patent segments the structure into regions with different optical path lengths. The first region has a first optical path length and the second region has a second optical path length. This segmentation, while increasing manufacturing complexity, dramatically improves light extraction efficiency by enabling extraction of both normal and oblique light at optimized wavelengths.
Solution Approach 2:
The resonator structure employs local differentiation of optical path lengths to optimize performance. The central region has optical path length optimized for normal light extraction, while the peripheral region has optical path length optimized for oblique light extraction. This local quality variation enables high light extraction efficiency across different angles and wavelengths.
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 enables efficient extraction of desired wavelengths while maintaining high color purity, improving luminance and light extraction efficiency by optimizing the optical path lengths and surface flatness within the resonator structure.
Implementation Method 1
a resonator structure configured to resonate, between the reflective film and the second electrode, light generated in the organic film
Data Source
AI summary
A light emitting device in which a reflective film, a first electrode, an organic film including a light emitting layer, a second electrode, and an optical member are arranged in this order on a principal surface of a substrate and a bank configured to cover a peripheral portion of the first electrode is provided to define a light emitting region. The reflective film, the first electrode, the organic film, and the second electrode form a resonator structure configured to resonate, between the reflective film and the second electrode, light generated in the organic film. In the light emitting region, an upper surface of the reflective film is flatter than the first electrode. The resonator structure has a plurality of different optical path lengths.