Fourier Beam Uniformization for Stable Light Modulator Illumination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current projection systems waste significant light energy due to non-uniform illumination and light leakage, leading to reduced contrast and inefficient use of light modulators, with issues exacerbated by differential temperature and aging effects among discrete laser sources.
Innovation Solution
A system utilizing two uniformization structures, such as optical fibers, with a Fourier optical system in between, to ensure uniform spatial and angular distribution of light beams, minimizing light loss and speckle effects, and stabilizing the light profile across the first light modulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a circular light beam with Gaussian profile is used to illuminate a rectangular light modulator, then the light beam can be efficiently focused, but the peak power illumination load becomes a multiple of the peak power illumination load for uniform rectangular illumination, pushing local temperature beyond normal operating range and decreasing device lifetime
Solution Approach 1:
The patent applies parameter changes by transforming the light beam profile from Gaussian to uniform rectangular distribution. This is achieved through optical systems that modify the spatial and angular parameters of the light beam, redistributing the intensity across the rectangular modulator area to achieve uniform illumination. This resolves the contradiction by maintaining focusing efficiency while preventing excessive peak power concentration that would cause temperature rise.
Solution Approach 2:
The patent introduces intermediary optical components (such as beam shaping optics, diffusers, or integrating rods) between the light source and the light modulator. These intermediaries act as mediators that transform the Gaussian beam into a uniform rectangular distribution, redistributing the thermal load across the entire modulator surface rather than concentrating it at peak intensity points.
2Area of stationary object
If multiple discrete laser sources are combined to illuminate the first light modulator, then the light coverage can be extended, but differential temperature- or aging effects between the discrete laser sources result in a modified illumination profile that is difficult to predict over the lifetime of the device
Solution Approach 1:
The patent uses intermediary optical components (such as diffusers, integrating rods, or optical fibers) that act as mediators between the multiple laser sources and the light modulator. These intermediaries mix the light from different sources and redistribute it uniformly across the modulator surface, thereby stabilizing the illumination profile over time and reducing sensitivity to individual source variations due to temperature or aging.
Solution Approach 2:
The patent changes the spatial and angular parameters of the light distribution by introducing optical systems that transform the combined laser illumination into a uniform rectangular profile. This parameter transformation ensures that the overall illumination remains stable and predictable, compensating for variations introduced by multiple discrete sources.
3Reliability
If a cascade of 2 light modulators is used to lower light leakage in black, then contrast can be improved, but light throughput efficiency is significantly reduced as losses in the first light modulator reduce the peak brightness level by 50%
Solution Approach 1:
The patent introduces an intermediary light steering modulator that selectively directs light to the second light modulator only where needed. This intermediary component acts as a gatekeeper, preventing unnecessary light from reaching the second modulator and thereby reducing overall light loss while maintaining effective light blocking performance where required.
Solution Approach 2:
Instead of using both light modulators at full capacity continuously, the patent applies partial action by using the first light modulator to pre-filter and steer light, allowing the second light modulator to operate more efficiently only for specific regions. This partial utilization approach reduces cumulative losses compared to having both modulators operate at full capacity throughout.
4Illumination intensity
If the light beam is focused to a small spot, then the peak brightness level increases, but the angular spread causes the light spot to be blurred around the optical axis
Solution Approach 1:
The patent changes the angular parameters of the light beam by introducing optical systems that control and minimize angular spread. This includes using beam collimators, precision focusing optics, or adaptive optics to maintain a tight, sharp focus while achieving high peak brightness levels, thereby resolving the contradiction between intensity and sharpness.
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
Achieves uniform illumination across the light modulator, reducing thermal stress, extending device lifespan, and enhancing contrast and brightness levels without increasing average picture brightness, while stabilizing against differential temperature and aging effects.
Implementation Method 1
at least two uniformization structures, for example optical fibres, each having an input- and an exit
Implementation Method 2
a Fourier optical system having a first and second focal point. The light source, the first uniformization structure, the Fourier optical system and the second uniformization structure can be placed immediately and consecutively after each other
Data Source
AI summary
An imaging projection system that can project uniform illumination onto a light modular while keeping the point spread function small. A Fourier optical system can be inserted between two uniformization structures so that when light passes the through the system, the light output is uniform both in spatial- and angular space.