Reflective Polarizer with Non-Overlapping Bands for OLED Displays
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Solution Overview
Problem
Organic light emitting diode (OLED) displays face challenges in reducing ambient light reflection while maintaining brightness and color gamut without causing ghosting or image degradation.
Innovation Solution
A reflective polarizer with non-overlapping reflection bands is integrated into the circular polarizer of the OLED display, utilizing alternating polymeric interference layers to selectively reflect and transmit light, optimizing the reflection band edges to minimize ghosting and enhance brightness and color gamut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a broadband reflective polarizer is used to reduce ambient light reflection, then reflection reduction is improved, but brightness and color gamut are reduced
Solution Approach 1:
The reflective polarizer is segmented into multiple interference layers (first, second, third, and fourth interference layers) with different optical properties. Each layer is designed to reflect specific wavelength ranges, creating a segmented spectral reflection profile that reduces ambient light across the visible spectrum while maintaining transmission in the OLED emission bands, thereby preserving brightness and color gamut.
2Object-affected harmful factors
If a broadband reflective polarizer is used to reduce ambient light reflection, then reflection reduction is improved, but ghosting increases
Solution Approach 1:
Different regions of the reflective polarizer structure are assigned different local optical qualities. The first and second interference layers have optical properties optimized for reflecting specific wavelength ranges, while the third and fourth layers have complementary properties. This local quality differentiation creates a spectrally selective reflection profile that reduces ambient light without causing ghosting by avoiding uniform broadband reflection.
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 solution increases on-axis brightness by at least 15% and color gamut by at least 2% of NTSC, while reducing ambient reflection by 38% compared to using a broadband reflective polarizer, with minimal ghosting.
Implementation Method 1
The reflective polarizer includes a plurality of alternating polymeric interference layers and has substantially non-overlapping first, second, and third reflection bands
Implementation Method 2
At normal incidence, the first reflection band has a long wavelength band edge wavelength between peak emission wavelengths of two subpixels in the plurality of subpixels
Data Source
AI summary
A display (1000) including a display panel (130) and a polarizer (110) disposed to receive a light (150) output of the display panel (130) is described. The polarizer (150) may be a reflective polarizer (110) or a circular polarizer (100) incorporating a reflective polarizer (110). The display panel (130) includes a plurality of pixels and each pixel includes a plurality of subpixels. The reflective polarizer (110) has a first reflection band, wherein at normal incidence, the first reflection band has a long wavelength band edge wavelength between peak emission wavelengths of two subpixels in the plurality of subpixels. The reflective polarizer (110) may be disposed between an absorbing polarizer (106) and a retarder (108) in a circular polarizer (100). The reflective polarizer (110) may have substantially non-overlapping first, second, and third reflection bands.