Reflective OLED with Embedded Color Filters
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Solution Overview
Problem
Conventional organic light emitting displays suffer from low color reproducibility due to light leakage between the color filter and the organic light emitting device, resulting in poor color purity.
Innovation Solution
The organic light emitting display incorporates a reflective layer, color filters of varying thicknesses (red, green, blue) with a transflective second electrode, and a transparent encapsulating member, where the resonance distance of light emitted from the emitting layer matches the distance between the reflective layer and the second electrode, enhancing color extraction and reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If color filters are disposed on one surface of the counter substrate in conventional organic light emitting displays, then the device structure is simple and easy to manufacture, but light leakage occurs between the color filter and the organic light emitting device resulting in poor color purity
Solution Approach 1:
The color filter is integrated within the organic light emitting device structure by positioning it between the first electrode and the organic layer, creating a nested configuration where the color filter is embedded within the device stack rather than being a separate external component. This nesting eliminates light leakage paths while maintaining manufacturing feasibility
Solution Approach 2:
The first electrode serves as an intermediary component that simultaneously functions as an electrical electrode and a support substrate for the color filter. This intermediary role allows the color filter to be properly positioned and secured within the device structure, preventing light leakage while maintaining ease of assembly
2Manufacturing precision
If the resonance distance between the reflective layer and the transflective second electrode is optimized for each color filter, then color reproducibility is enhanced, but the device structure becomes more complex
Solution Approach 1:
The distance between the reflective layer and the transflective second electrode is locally optimized for each color filter type (red, green, blue), with each color having a specific resonance distance tailored to its wavelength characteristics. This local quality approach enhances color reproducibility for each subpixel while maintaining overall device functionality
Solution Approach 2:
The optical parameters of the device are adjusted by varying the distance between the reflective layer and the transflective second electrode according to the specific wavelength requirements of each color filter. This parameter change strategy allows optimization of light resonance and extraction efficiency for different colors without fundamentally changing the device architecture
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 prevents light leakage and improves color reproducibility by ensuring that light of specific wavelengths corresponding to the color filters is extracted, resulting in enhanced color purity and display performance.
Implementation Method 1
a reflective layer on the thin film transistor substrate
Implementation Method 2
a plurality of color filters on the reflective layer, the plurality of color filters including red, green, and blue color filters having different thicknesses
Implementation Method 3
a transflective second electrode on the organic layer
Implementation Method 4
holes and electrons are injected into the organic layer from the anode electrode and the cathode electrode and are recombined in the organic layer to generate excitons. When the excitons drop from an excited state to a ground state, energy is emitted in the form of light
Data Source
AI summary
An organic light emitting display includes a thin film transistor substrate, and an organic light emitting device on the thin film transistor substrate, the organic light emitting device including a first electrode on the thin film transistor substrate, the first electrode being configured to reflect light, an organic layer on the first electrode and including at least an emitting layer, a transflective second electrode on the organic layer, and a color filter between the first electrode and the transflective second electrode.