Optical Member for OLED Luminance and Reflectance Control
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Solution Overview
Problem
Organic light-emitting display devices face reduced luminance due to high reflectance caused by circular polarizers, which also increase unreliability and smudge risk when trying to enhance transmittance.
Innovation Solution
An optical member comprising a linear polarizer, a blue cholesteric liquid crystal layer that transmits either left- or right-handed circularly polarized light, and a quarter wave plate to convert this light into linear polarized light, positioned on the same side of the linear polarizer, is used to enhance luminance while reducing reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a circular polarizer is used to reduce reflection, then reflectance is reduced, but luminance is reduced by at least 50%
Solution Approach 1:
The circular polarizer is divided into two separate functional layers: a linear polarizer layer and a quarter wave plate layer. This segmentation allows each layer to perform its specific optical function independently, enabling the linear polarizer to reduce reflection while the quarter wave plate converts polarization states to maintain luminance.
Solution Approach 2:
Instead of using a conventional circular polarizer that directly reduces luminance, the patent inverts the approach by using a linear polarizer combined with a quarter wave plate. The quarter wave plate converts linearly polarized light to circularly polarized light (or vice versa), achieving reflection reduction while preserving luminance through this inverted optical path.
2Illumination intensity
If transmittance of the linear polarizer is increased to enhance luminance, then luminance is improved, but reflectance increases again
Solution Approach 1:
The quarter wave plate acts as an intermediary element between the linear polarizer and the external environment. It mediates the optical interaction by converting polarization states, allowing the linear polarizer to maintain high transmittance for luminance enhancement while the quarter wave plate manages the reflection characteristics through polarization conversion.
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 achieves high luminance with low reflectance, maintaining overall reflectance below 1% and improving efficiency by recycling reflected light, thus enhancing the visibility and reducing power consumption of organic light-emitting display devices.
Implementation Method 1
a blue cholesteric liquid crystal (CLC) layer configured to transmit light, the light having only one of: a left-handed circularly polarized light component and a right-handed circularly polarized light component
Implementation Method 2
a quarter wave plate configured to convert the transmitted light, having the left-handed circularly polarized light component or right-handed circularly polarized light component, into linear polarized light
Implementation Method 3
a linear polarizer
Data Source
AI summary
Provided are an optical member for enhancing luminance and an organic light-emitting display device having the same. An optical member includes: a linear polarizer, a blue cholesteric liquid crystal (CLC) layer configured to transmit light, the light having only one of: a left-handed circularly polarized light component and a right-handed circularly polarized light component, and a quarter wave plate configured to convert the transmitted light, having the left-handed circularly polarized light component or right-handed circularly polarized light component, into linear polarized light, wherein the blue cholesteric liquid crystal (CLC) layer and the quarter wave plate are located on a same side of the linear polarizer.