Polarization Conversion System for High Dynamic Range Projection
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Solution Overview
Problem
Current projection systems have limited dynamic range and intra-frame contrast, failing to accurately represent the wide luminance range of the human eye, leading to reduced image quality due to light leakage and scattering issues.
Innovation Solution
A polarization conversion system (PCS) is introduced, utilizing a polarization beam splitter, optical stacks, and high dynamic range modulators to split and modulate light into different polarization states, enhancing the dynamic range and contrast by directing light along specific paths and incorporating a high resolution spatial light modulator, such as a 4K DLP, to adjust transmission and reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional projection system is used, then the system structure is simple, but the dynamic range and intra-frame contrast are limited
Solution Approach 1:
The projection system is segmented into multiple optical paths (first light path and second light path) with separate modulation stages. The polarization beam splitter divides the light into different polarization states that are modulated independently, allowing the system to achieve high dynamic range by processing different luminance levels through different paths rather than using a single complex modulator.
Solution Approach 2:
The patent implements nested modulation by placing a first modulator and a second modulator in series within the optical path. The first modulator performs coarse modulation and the second modulator performs fine modulation, creating a nested structure where one modulation stage is embedded within another to achieve extended dynamic range.
2Illumination intensity
If a conventional projection system is used, then the device complexity is low, but the intra-frame contrast is insufficient due to light leakage and scattering
Solution Approach 1:
The patent extracts and separates the modulation function into distinct stages and optical paths. By taking out the modulation process from a single integrated component and distributing it across multiple specialized modulators in different optical paths, the system achieves better contrast by preventing light leakage and scattering that would occur in a single-path system.
Solution Approach 2:
The polarization beam splitter acts as an intermediary that separates light into different polarization states before modulation. This intermediary component enables the system to handle different luminance levels separately, improving contrast by preventing mixing of light paths that would cause scattering and reduce image quality.
3Illumination intensity
If light is not split into different polarization states, then the optical system is simpler, but the dynamic range cannot be extended
Solution Approach 1:
The patent introduces polarization state as an additional dimension for light manipulation. By splitting light into different polarization states (first polarization state and second polarization state) and processing them through separate optical paths, the system extends its dynamic range capability without requiring a single extremely complex modulator, effectively using polarization as an extra degree of freedom.
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 PCS significantly improves the dynamic range and intra-frame contrast of projected images, enabling the display of high peak brightness and deep black levels, thereby enhancing the perceived image quality by effectively managing light leakage and scattering.
Implementation Method 1
a polarization beam splitter (PBS) operable to receive randomly polarized light from a projection system, and operable to direct light with a first polarization state along a first light path and operable to direct light with a second polarization state along a second light path
Implementation Method 2
The modulator may also be a global modulator. Additionally, the modulator may be achromatic.
Implementation Method 3
The high resolution spatial light modulator may change the transmission or reflection of light. One example of a high resolution spatial light modulator is a 4K digital light processing projector (DLP).
Data Source
AI summary
Display devices with high dynamic ranges approaching the limitations of the human eye are discussed herein. High dynamic range projections systems may be 2D or 3D and devices may or may not be implemented with polarization preserving optics for high efficiency. In one embodiment, 2D HDR projection systems may compensate the modulator for varying transmission and contrast versus field of view. In another embodiment, 3D HDR projection systems may include a global or pixelated/segmented modulator. The global or pixelated/segmented modulator may be included in a stereoscopic polarization switch or in a polarization-preserving stereoscopic projection system. Additionally, a combination of global/global or pixelated/pixelated, or global/pixelated modulators may be used.