Multilayer Reflective Polarizer With Sloped Block Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional reflective polarizers face challenges in achieving optimal transmission and reflection properties across a wide spectral range while maintaining a thin profile, often resulting in a tradeoff between thickness and optical performance, which affects contrast ratio and brightness in display devices.
Innovation Solution
The development of a reflective polarizer with a tailored layer profile that achieves a sloped block state transmission spectrum, allowing for increased block light transmission in certain wavelengths without compromising pass light transmission, especially at oblique angles, and when combined with an absorbing polarizer, this configuration enhances contrast ratio and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the reflective polarizer uses a conventional uniform layer profile, then it achieves adequate block light transmission, but the pass light transmission at oblique angles deteriorates and the contrast ratio decreases
Solution Approach 1:
The patent applies local quality by implementing a non-uniform layer profile where the thickness of optical layers varies across the film structure. Specifically, the layer profile is designed with different thickness regions to optimize both pass light transmission at oblique angles and block light rejection, thereby maintaining high contrast ratio. This localized variation in layer thickness allows different portions of the polarizer to perform specialized functions.
2Length of moving object
If the reflective polarizer is made thinner to improve display device integration, then manufacturing and optical performance deteriorate
Solution Approach 1:
The patent applies parameter changes by systematically varying the thickness parameters of individual optical layers within the multilayer structure. By adjusting these thickness parameters according to a specific non-uniform profile, the polarizer achieves enhanced optical performance in a thinner overall configuration. This parameter optimization allows the thin polarizer to maintain adequate block light transmission while improving pass light transmission at oblique angles.
3Illumination intensity
If the reflective polarizer increases block light transmission in certain wavelengths to improve brightness, then the contrast ratio deteriorates
Solution Approach 1:
The patent applies local quality by implementing a non-uniform layer profile where the thickness of optical layers varies across the film structure. Specifically, the layer profile is designed with different thickness regions to optimize both pass light transmission at oblique angles and block light rejection, thereby maintaining high contrast ratio. This localized variation in layer thickness allows different portions of the polarizer to perform specialized functions.
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 reflective polarizer achieves improved contrast ratio and brightness in display devices by maintaining high pass light transmission and selectively increasing block light transmission in specific wavelengths, while maintaining a thin profile, thus overcoming the traditional tradeoff between thickness and optical performance.
Implementation Method 1
Multilayer optical films are formed by coextruding tens to hundreds of molten polymer layers and subsequently orientating or stretching the resulting film
Implementation Method 2
Multilayer optical films are formed by coextruding tens to hundreds of molten polymer layers and subsequently orientating or stretching the resulting film
Implementation Method 3
The multilayer optical film can include alternating birefringent and isotropic layers
Data Source
AI summary
Multilayer reflective polarizers are described. More particularly, multilayer reflective polarizers having a higher block light transmission at longer wavelengths than shorter wavelengths while having a high pass light transmission are described. The described multilayer reflective polarizers may be combined with absorbing polarizers or used in display devices.