Reflective Polarizer Bands for OLED Color and Ghosting Control
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Solution Overview
Problem
Existing OLED displays face challenges in maintaining color gamut and reducing ghosting while effectively managing ambient light reflection, particularly at off-normal viewing angles.
Innovation Solution
A reflective polarizer with distinct blue, green, and red-infrared reflection bands and an absorption peak between the green and red FWHMs is used, along with a retarder layer and absorbing polarizer, to enhance light recycling and reduce color shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a circular polarizer is used to reduce ambient light reflection, then reflection is reduced, but color gamut and ghosting performance deteriorate
Solution Approach 1:
The polarizer is segmented into multiple functional layers: a reflective polarizer with distinct blue, green, and red-infrared reflection bands, and an absorbing polarizer. This segmentation allows each layer to handle specific wavelength ranges and polarization states independently, reducing ambient light reflection while preserving color gamut and minimizing ghosting effects that plague single-layer circular polarizers.
Solution Approach 2:
The invention employs a composite structure combining a reflective polarizer (with specific reflection bands at blue, green, and red-infrared wavelengths) and an absorbing polarizer. This composite material approach enables simultaneous achievement of reflection reduction and color accuracy maintenance, resolving the contradiction between reflection control and color gamut preservation.
2Illumination intensity
If light recycling is enhanced to improve brightness, then brightness increases, but color shift and ghosting increase
Solution Approach 1:
The reflective polarizer exhibits local quality in its optical properties, with distinct reflection bands at specific wavelengths (blue, green, and red-infrared) rather than uniform reflection across all wavelengths. This wavelength-selective reflection enables targeted light recycling that enhances brightness while maintaining color accuracy and reducing ghosting by reflecting only specific spectral components.
Solution Approach 2:
The invention changes the optical parameters of the polarizer system by introducing a reflective polarizer with specific reflection bands at blue, green, and red-infrared wavelengths, along with an absorption peak between the green and red bands. This parameter optimization enables effective light recycling for brightness enhancement while controlling color shift and ghosting through selective wavelength reflection and absorption.
3Adaptability or versatility
If viewing angle is increased to expand field of view, then field of view expands, but color accuracy deteriorates
Solution Approach 1:
The reflective polarizer dynamically adapts its optical performance across different viewing angles through its specific reflection band structure. The distinct blue, green, and red-infrared reflection bands maintain their effectiveness across a wide viewing angle range, enabling the display to preserve color accuracy even when viewed from oblique angles, thus expanding the effective field of view without sacrificing color fidelity.
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
Improves color gamut and reduces ghosting, maintaining color accuracy across viewing angles by optimizing light reflection and transmission properties.
Implementation Method 1
the reflective polarizer has a reflection spectrum including substantially distinct blue, green and red-infrared reflection bands
Implementation Method 2
reflects at least about 60% of the incident light for each of the blue and green peak wavelengths and at least about 40% of the incident light for the red peak wavelength for a first polarization state; transmits at least about 60% of the incident light for each of the blue, green and red peak wavelengths for an orthogonal second polarization state
Implementation Method 3
has an absorption peak at a wavelength between the green and red FWHMs of the respective green and red emission spectra
Data Source
AI summary
A reflective polarizer has substantially distinct blue, green and red-infrared reflection bands for substantially normally incident light. A display system includes a display panel including blue, green and red light emitting pixels having respective blue, green and red peak wavelengths and respective blue, green and red FWHMs; and the reflective polarizer disposed on the light emitting pixels. The reflective polarizer: reflects at least about 60% of the incident light for each of the blue and green peak wavelengths and at least about 40% of the incident light for the red peak wavelength for a first polarization state; transmits at least about 60% of the incident light for each of the blue, green and red peak wavelengths for an orthogonal second polarization state; and has an absorption peak at a wavelength between the green and red FWHMs.