Optical Sheet with Random Light-Scattering Elements for OLED Color-Shift Reduction
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Solution Overview
Problem
Organic light emitting display (OLED) devices suffer from low light emitting efficiency due to broad light emitting wavelengths and random light orientation, which causes color-shifts at different viewing angles, affecting image visibility.
Innovation Solution
An optical sheet with randomly and nonperiodically distributed light-scattering elements, including a binding-material member and light-scattering particles, is integrated into the OLED device. The weight percent of light-scattering particles and the configuration value calculated from the thickness, weight percent, and average distance of these elements are optimized to minimize color-shift and enhance image visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a light extraction structure or resonance structure is implemented in the OLED device, then light emitting efficiency is improved, but color-shifts occur at different viewing angles
Solution Approach 1:
The patent changes the distribution pattern parameter of light-scattering elements from periodic to random and nonperiodic arrangement. This parameter change allows the optical sheet to scatter sidelight effectively without causing color-shifts at different viewing angles, while maintaining improved light emitting efficiency through enhanced light extraction.
Solution Approach 2:
The patent applies light-scattering elements with specific properties (random distribution, controlled size range of 1-10 μm, specific weight percent 5-40%) at different locations within the optical sheet. This local quality approach ensures that sidelight is scattered appropriately at each viewing angle without introducing color-shifts, while maintaining overall light extraction efficiency.
2Use of energy by moving object
If light-scattering elements are added to improve light extraction, then light emitting efficiency is improved, but device complexity increases
Solution Approach 1:
The patent merges the light-scattering elements directly into the optical sheet substrate, forming an integrated structure where the optical sheet and light-scattering elements become a single component. This merging approach improves light emitting efficiency through effective light extraction while avoiding the complexity of separate light extraction structures.
Solution Approach 2:
The patent uses light-scattering elements that create a microscopically porous or heterogeneous structure within the optical sheet. This approach enhances light extraction and emitting efficiency by increasing light path length and scattering opportunities, while the elements are embedded in a way that maintains overall structural simplicity.
3Object-affected harmful factors
If light-scattering particles are dispersed in binding-material member, then light scattering effectiveness is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies parameter ranges for light-scattering particle size (1-10 μm) and weight percent (5-40%) to optimize scattering effectiveness. By defining these parameters as ranges rather than fixed values, the patent accommodates manufacturing variations while maintaining effective sidelight scattering performance.
Solution Approach 2:
The patent allows random and nonperiodic distribution of light-scattering elements throughout the optical sheet, accepting local variations in distribution patterns. This approach improves sidelight scattering effectiveness by ensuring coverage across different viewing angles, while the random distribution naturally tolerates manufacturing precision variations.
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 optical sheet significantly reduces color-shift and improves transmittance efficiency, maintaining high image brightness and visibility across various viewing angles by scattering sidelight effectively.
Implementation Method 1
light-scattering elements, including a binding-material member and light-scattering particles dispersed in (or inside) the binding-material member
Data Source
AI summary
An optical sheet includes a transparent substrate. The optical sheet further includes light-scattering elements randomly and nonperiodically distributed in the transparent substrate. Each light-scattering element of the light scattering elements includes a binding-material member and light-scattering particles dispersed in the binding-material member. A weight percent calculated from dividing a total weight of light-scattering particles of the light-scattering elements by a total weight of the light-scattering elements is in a range of 5 wt % to 40 wt %.