Light Homogenization Module with Segmented Integration Rod
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Solution Overview
Problem
Current projector technologies using pure laser light sources struggle with speckles due to the point light source array's limitations in angular distribution and chief ray angle, which current diffusers and beam splitters fail to adequately address, resulting in poor color purification and gamut performance.
Innovation Solution
A light homogenization module with an integration rod featuring a first and second diffusively reflective element with different hazes on its inner surface, which effectively homogenizes light by optimizing reflections at various angles, reducing speckle contrast and energy loss, and facilitating miniaturization of the projection apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a point light source array is used as a laser light source, then color purification and color gamut are improved, but speckles are generated due to limitations in angular distribution and chief ray angle
Solution Approach 1:
The integration rod is segmented into multiple sections with different diffusively reflective elements (first and second diffusively reflective elements with different hazes) positioned at different locations. This segmentation allows different angular ranges of light to be treated differently, homogenizing the light while preserving color purification properties.
Solution Approach 2:
Different portions of the integration rod inner surface are assigned different properties through the first and second diffusively reflective elements with different hazes. The first diffusively reflective element has greater haze for certain angular ranges while the second has lesser haze for other angular ranges, creating local quality variations that achieve overall light homogenization.
2Object-generated harmful factors
If current diffusers or beam splitters are used, then some speckle reduction is achieved, but color purification and color gamut performance remain poor
Solution Approach 1:
The integration rod acts as an intermediary component between the laser light source and the projection lens. It mediates the light transformation by homogenizing the angular distribution through its internal diffusively reflective elements while maintaining the color purification capability, thus resolving the conflict between speckle reduction and color quality.
3Object-generated harmful factors
If a long integration rod is used to achieve complete light homogenization, then speckle contrast is reduced, but the overall volume of the projection apparatus increases
Solution Approach 1:
Instead of using a uniformly long integration rod, the patent places diffusively reflective elements with different hazes at specific locations within the integration rod. This localized approach achieves effective homogenization for incident lights at different angles without requiring excessive rod length, thus reducing the overall volume.
Solution Approach 2:
The patent changes the haze parameter of the diffusively reflective elements to optimize light homogenization. By selecting appropriate haze values for the first and second diffusively reflective elements, the system achieves effective speckle reduction in a compact integration rod length, balancing homogenization effectiveness with device miniaturization.
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 solution achieves effective despeckling, improved light homogenization, and enhanced color purification, leading to better image quality while minimizing the overall volume of the projection apparatus.
Implementation Method 1
The first diffusively reflective element is disposed on the inner surface of the integration rod. The second diffusively reflective element is disposed on the inner surface of the integration rod and adjacent to the first diffusively reflective element.
Implementation Method 2
A haze of the first diffusively reflective element is greater than a haze of the second diffusively reflective element
Data Source
AI summary
A light homogenization module includes an integration rod, a first diffusively reflective element, and a second diffusively reflective element. The integration rod has a light inlet and an inner surface. The first diffusively reflective element is disposed on the inner surface of the integration rod. The second diffusively reflective element is disposed on the inner surface of the integration rod and adjacent to the first diffusively reflective element. The second diffusively reflective element is disposed between the first diffusively reflective element and the light inlet of the integration rod. A haze of the first diffusively reflective element is greater than a haze of the second diffusively reflective element. A projection apparatus is also provided.