Hybrid Polarizer for OLED Luminance and Glare Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Emissive displays, such as OLEDs, face challenges with existing circular polarizers that absorb a significant amount of emitted light and are costly due to complex alignment requirements, limiting display contrast and brightness in various ambient environments.
Innovation Solution
The implementation of a hybrid polarizer configuration using birefringent reflective and linear absorbing polarizers, along with a structured optical film or non-polarization preserving element, which simplifies the anti-reflection stack and enhances light outcoupling, allowing for improved optical properties and reduced production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional circular polarizer (linear absorbing polarizer + 1/4 wave film) is used to reduce ambient light reflection, then the display contrast is improved, but the emitted light is absorbed by 50% or more and the production cost increases due to complex alignment requirements
Solution Approach 1:
The patent divides the anti-reflection function into separate components: a linear absorbing polarizer for glare reduction and a birefringent reflective polarizer for light management. This segmentation allows each component to perform its specific function optimally without the light absorption penalties of a conventional circular polarizer stack.
Solution Approach 2:
Instead of using a linear absorbing polarizer combined with a 1/4 wave film (conventional approach), the patent inverts the approach by using a birefringent reflective polarizer that reflects rather than absorbs light. This inversion changes the mechanism from absorption-based to reflection-based, thereby reducing energy loss.
2Object-affected harmful factors
If a conventional circular polarizer with 1/4 wave film is used, then the display contrast is improved, but the production cost increases due to the difficulty of aligning the pass axis of the linear polarizer and the fast or slow axis of the 1/4 wave film at 45 degrees
Solution Approach 1:
The patent extracts the 1/4 wave film from the anti-reflection stack, removing the source of alignment complexity. By using a birefringent reflective polarizer without a quarter-wave plate, the system eliminates the difficult 45-degree alignment requirement while maintaining effective glare reduction.
Solution Approach 2:
The patent inverts the conventional circular polarizer architecture by replacing the absorbing linear polarizer + 1/4 wave film combination with a reflective birefringent polarizer. This architectural inversion fundamentally changes the alignment requirements and simplifies the manufacturing process.
3Object-affected harmful factors
If a conventional circular polarizer is used, then the ambient reflectance is reduced, but the display brightness and power efficiency are cut by more than half
Solution Approach 1:
The patent converts the harmful effect of light absorption into beneficial light reflection. The birefringent reflective polarizer reflects the blocked polarization state back toward the OLED, where it can be re-emitted, thereby converting what would have been lost light into useful display brightness.
Solution Approach 2:
The patent employs a composite optical system combining a linear absorbing polarizer with a birefringent reflective polarizer. This composite structure leverages the glare-reduction capability of the linear polarizer while the reflective polarizer component recycles light, together achieving both low reflectance and high brightness.
4Object-affected harmful factors
If a high performance circular polarizer is used to maintain required contrast in bright ambient environments, then the contrast is improved, but the cost of the CP film stack increases
Solution Approach 1:
The patent replaces expensive high-performance circular polarizer film stacks with a combination of more affordable polarizing components. The linear absorbing polarizer and birefringent reflective polarizer can be manufactured and assembled at lower cost while achieving comparable or superior performance in bright ambient conditions.
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 enhances luminance efficiency by up to 4.0 times compared to conventional circular polarizers while maintaining reduced glare from ambient light, without compromising color uniformity across viewing angles.
Implementation Method 1
a first and second birefringent reflective polarizer
Implementation Method 2
a first and second linear absorbing polarizer
Implementation Method 3
a structured optical film
Data Source
AI summary
An emissive display comprising an OLED, a first birefringent reflective polarizer, a second birefringent reflective polarizer optically between the OLED and the first birefringent reflective polarizer, a first linear absorbing polarizer having a contrast ratio of less than 100:1 optically between the first birefringent reflective polarizer and the second birefringent reflective polarizer, a second linear absorbing polarizer having a contrast ratio of less than 100:1, where the first birefringent reflective polarizer is optically between the second linear absorbing polarizer and the first linear absorbing polarizer, and a structured optical film optically between the OLED and the second birefringent reflective polarizer.