OLED Display Color Shift Correction Using Quarter-Wavelength Retarder
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Solution Overview
Problem
Organic light emitting diode displays experience color-shift at wide viewing angles due to the blue shift phenomenon, where the spectrum of light emitted shifts towards shorter wavelengths, causing white images to appear greenish, and existing solutions with positive C-plates are costly and difficult to develop.
Innovation Solution
An organic light emitting diode display structure comprising a quarter-wavelength retarder, a polarizer, and a diffraction grating film with multiple layers and gratings aligned in specific directions, which redirects light to maintain color consistency across viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a top emitting mode organic light emitting diode with semi-transparent electrode is used to achieve better luminous efficiency, then luminous efficiency is improved, but color-shift at wide viewing angles occurs due to micro-resonant cavity effect
Solution Approach 1:
A quarter-wavelength retarder is introduced as an intermediary optical element between the organic light emitting diode and the viewer. This retarder compensates for the phase difference between orthogonal polarization components of light, thereby correcting the color-shift caused by the micro-resonant cavity effect at wide viewing angles while preserving the high luminous efficiency of the top emitting mode structure
Solution Approach 2:
The optical parameters of the display system are modified by adding the quarter-wavelength retarder, which changes the polarization state and phase relationship of the emitted light. This parameter change compensates for the viewing angle-dependent color-shift without requiring changes to the core OLED structure that would affect luminous efficiency
2Ease of manufacture
If existing positive C-plate materials with reverse dispersion property are used to improve color-shift problem, then color-shift is reduced, but manufacturing cost increases and development difficulty increases
Solution Approach 1:
The patent replaces expensive and difficult-to-develop positive C-plate materials with a quarter-wavelength retarder, which is a more commercially成熟 and easier to manufacture optical component. This substitution achieves similar color-shift correction functionality while significantly reducing material costs and development complexity
Solution Approach 2:
Instead of relying on the complex reverse dispersion properties of positive C-plates, the solution changes the optical approach by using a quarter-wavelength retarder that operates on phase compensation principles. This parameter change in the optical correction mechanism avoids the need for specialized expensive materials
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 effectively reduces color-shift at wide viewing angles, improving image quality by minimizing wavelength shift and maintaining color purity across different viewing angles.
Implementation Method 1
a quarter-wavelength retarder disposed on the organic light emitting diode panel
Implementation Method 2
a diffraction grating film disposed on the polarizer comprising a substrate and a first diffraction grating layer formed on the substrate
Implementation Method 3
The organic light emitting diodes can be distinguished into a top emitting mode and a bottom emitting mode organic light emitting diode according to different light-emitting directions
Data Source
AI summary
An organic light emitting diode display is provided. The organic light emitting diode display comprises an organic light emitting diode panel, a quarter-wavelength retarder disposed on the organic light emitting diode panel, a polarizer disposed on the quarter-wavelength retarder, an adhesive layer disposed on the polarizer and a diffraction grating film adhered to the polarizer by the adhesive layer. The diffraction grating film comprises a substrate and a first diffraction grating layer comprising a plurality of first gratings aligned with a first direction disposed on the substrate.