Polarizing Beam Splitter Plate Flatness for High Resolution
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Solution Overview
Problem
Current polarizing beam splitters, particularly those using multilayer optical films, face challenges in achieving high effective resolution for reflected imaged light, especially in three-dimensional projection and imaging applications, where distortion and low resolution are common issues due to difficulties in formulating flat reflective polarizers that can handle a wide range of angles and wavelengths effectively.
Innovation Solution
The development of a polarization subsystem that incorporates a reflective polarizer made from a multilayer optical film with a surface roughness of less than 45 nm, positioned between glass or optical plastic covers, and processed using techniques such as vacuum treatment to achieve exceptional flatness and high effective pixel resolution of less than 12 microns, potentially down to 6 microns, for reflected imaged light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a multilayer optical film reflective polarizer is used in a polarizing beam splitter, then the ability to handle a wide range of angles and wavelengths is improved, but the effective resolution of reflected imaged light deteriorates due to distortion
Solution Approach 1:
The patent applies local quality by creating a localized flat region on the reflective polarizer surface. Specifically, a portion of the multilayer optical film is flattened to a surface roughness of less than 45 nm RMS within a defined area, while other portions can maintain their original microstructured morphology. This localized flattening preserves the polarization functionality across different angles and wavelengths while eliminating surface-induced distortion in the critical imaging region, thereby achieving both adaptability and high resolution simultaneously
Solution Approach 2:
The patent segments the reflective polarizer surface into functionally distinct regions: a flat region with surface roughness less than 45 nm RMS for high-resolution imaging, and other regions that may have different surface characteristics optimized for polarization performance. This segmentation allows each region to perform its specific function optimally without compromising the other, resolving the contradiction between versatility and resolution
2Manufacturing precision
If the surface roughness of the reflective polarizer is reduced to achieve high flatness, then the effective pixel resolution is improved, but the difficulty of manufacture increases
Solution Approach 1:
The patent introduces an intermediary flattening process that acts as a mediator between the original multilayer film structure and the final flat surface. This process selectively flattens only the necessary portions of the film to achieve the required surface roughness of less than 45 nm RMS, while preserving the underlying microstructured morphology that provides polarization functionality. This intermediary step makes high-precision manufacturing achievable without requiring complete restructuring of the entire film
Solution Approach 2:
The patent changes the surface roughness parameter of the reflective polarizer from typical values (which cause distortion) to a controlled value of less than 45 nm RMS in the flat region. This parameter change is achieved through selective flattening processes that modify only the surface topology while maintaining the functional microstructure, thereby improving resolution without making manufacturing prohibitively difficult
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 solution enables high-resolution imaging by ensuring the reflective polarizer's exceptional flatness, which prevents distortion and enhances the effective pixel resolution of reflected light, making it suitable for advanced projection systems, including three-dimensional imaging without the need for time sequencing or polarization sequencing.
Implementation Method 1
a multilayer optical film reflective polarizer that is adhered to the first substrate, the reflective polarizer substantially reflecting polarized light having a first polarization state and substantially transmitting polarized light having a second polarization state perpendicular to the first polarization state
Implementation Method 2
the polarizing beam splitter plate reflects the received first imaged light towards the viewer with the reflected first imaged light having an effective pixel resolution of less than 12 microns
Data Source
AI summary
A viewing device is disclosed. The device includes a projector that projects a first imaged light, and a polarizing beam splitter plate that receives the projected first imaged light from the projector and reflects the received first imaged light for viewing by a viewer. The polarizing beam splitter plate also receives a second image and transmits the second image for viewing by the viewer. The polarizing beam splitter plate includes a substrate and a multilayer optical film reflective polarizer that is adhered to the substrate. The reflective polarizer substantially reflects polarized light having a first polarization state and substantially transmits polarized light having a second polarization state perpendicular to the first polarization state. The polarizing beam splitter plate includes a first outermost major surface and an opposing second outermost major surface that makes an angle of less than about 20 degrees with the first outermost major surface. The polarizing beam splitter plate reflects the received first imaged light towards the viewer with the reflected first imaged light having an effective pixel resolution of less than 12 microns.