Polarization Conversion System for 3D Projection Brightness
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Solution Overview
Problem
Conventional polarization control systems in 3D projection theaters result in a dimmer image due to over 50% light absorption by polarizers, limiting theater size and viewer experience.
Innovation Solution
A polarization conversion system incorporating a polarization beam splitter, rotator, and switch, along with optical elements like curved surfaces, Fresnel or diffractive surfaces, and refractive elements, to compensate for magnification differences and distortion, ensuring brighter images by optimizing light paths and polarization states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a linear polarizer is used to control polarization state, then the polarization state is controlled, but more than 50% of light is absorbed resulting in a dimmer image
Solution Approach 1:
The patent extracts the harmful absorption function from the polarizer by replacing it with a polarization beam splitter that separates light bundles based on polarization state without absorbing light. The polarizer's polarization control function is retained while its light-absorbing property is removed through the use of beam splitting and recombination optics.
Solution Approach 2:
The patent introduces a polarization beam splitter as an intermediary device between the light source and the projection system. This mediator separates the light into different polarization states and directs them through different optical paths, enabling polarization control without the energy loss inherent in direct polarizer absorption.
2Loss of energy
If a polarization beam splitter is used to avoid light absorption, then light loss is reduced, but distortion mismatch occurs between different light paths
Solution Approach 1:
The patent applies local quality by introducing distortion compensation specifically in the optical path where distortion occurs. The first optical path includes distortion compensation optics tailored to correct the specific distortion characteristics of that path, while the second path maintains its original optics, creating locally optimized quality in each path.
Solution Approach 2:
The patent changes optical parameters by introducing distortion compensation optics that modify the magnification and distortion characteristics of the first light path. This parameter adjustment ensures that both light paths produce images with matching distortion and magnification, enabling proper image overlay.
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 system produces a significantly brighter screen image by minimizing light loss and improving image overlay, enhancing the 3D viewing experience and allowing larger theater configurations.
Implementation Method 1
a polarization beam splitter (PBS) operable to receive randomly-polarized light bundles from a projector lens, and direct first light bundles having a first state of polarization (SOP) along a first light path, and direct second light bundles having a second SOP along a second light path
Implementation Method 2
a polarization rotator located on the first light path, the polarization rotator being operable to translate the first SOP to the second SOP
Implementation Method 3
providing a curved surface on the fold mirror with optical power that compensates for the magnification difference
Implementation Method 4
adding a Fresnel or diffractive surface with optical power to the reflecting element to compensate for the magnification difference
Implementation Method 5
adding a refractive element (lens) between the reflecting element and polarization switch, or between the PBS and reflecting element
Data Source
AI summary
Optical systems having at least one polarization beam splitter (PBS) are operable to receive randomly-polarized light bundles from a projector lens. The PBS is further operable to direct light bundles having a state of polarization (SOP) along a light path and operable to direct other light bundles having a different SOP along different light paths. The light paths have optical path lengths which may differ. Each light path produces an image having a distortion which may differ from the distortion of an image produced by a different light path. A compensation in a light path is operable to convert a non-compensated distortion of an image into a compensated distortion that more closely matches the distortion of images in other light paths.