Asymmetrical Light Integration Rod for Projection Defocusing
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Solution Overview
Problem
Conventional projection apparatuses suffer from defocusing issues due to the oblique incidence of illumination beams on digital micro-mirror devices, leading to blurring and inefficient utilization of illumination beams, which increases production costs when attempting to correct with wedge light integration rods.
Innovation Solution
An asymmetrical light integration rod with unequal long and short sides is used, allowing the optical path lengths to approximate each other, reducing defocusing and blurring, and simplifying the manufacturing process by avoiding trapezoidal cuts, thus improving beam utilization and lowering production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a symmetrical light integration rod is used, then the structure is simple and manufacturing is easy, but the focal plane does not coincide with the DMD causing defocusing and blurring
Solution Approach 1:
The patent applies asymmetry by designing the light integration rod with unequal lengths: the first and second reflective plates have a first length, while the third and fourth reflective plates have a second length that is different from the first length. This asymmetric configuration adjusts the optical path lengths to make the focal plane coincide with the DMD chip, thereby resolving the defocusing problem while maintaining manufacturing feasibility.
2Manufacturing precision
If a wedge light integration rod is used to correct focal plane alignment, then the defocusing is reduced, but the manufacturing complexity and cost increase due to precise cutting requirements
Solution Approach 1:
The patent implements asymmetry through unequal plate lengths in the light integration rod, which achieves focal plane alignment without requiring the complex wedge shape with precise cutting angles. This approach reduces manufacturing complexity while maintaining the ability to correct defocusing issues.
Solution Approach 2:
The patent applies local quality by making specific modifications to only certain reflective plates (using different lengths for different plates) rather than requiring the entire structure to be a complex wedge shape. This localized adjustment simplifies manufacturing while achieving the desired optical alignment.
3Volume of moving object
If the illumination beam is obliquely incident on the DMD, then the projection apparatus can be compact, but the edges of the light spot blur due to defocusing
Solution Approach 1:
The asymmetric light integration rod design with unequal plate lengths compensates for the oblique incidence geometry, adjusting the optical paths so that the focal plane coincides with the DMD chip. This maintains the compact apparatus design while eliminating the edge blurring caused by defocusing.
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 asymmetrical light integration rod effectively reduces blurring and enhances the utilization of illumination beams, resulting in improved brightness and efficiency of display pictures while reducing production costs by minimizing scrap and cutting precision requirements.
Implementation Method 1
The illumination beam 112 from the light source module 110 enters the symmetrical light integration rod 140 through the light input end 144a, and is reflected many times
Data Source
AI summary
A light integration rod having a light input end and a light output end opposite to each other is provided. The light integration rod includes a first reflective plate, a second reflective plate, a third reflective plate and a fourth reflective plate. The second reflective plate is opposite to the first reflective plate. The third reflective plate and the fourth reflective plate connect the first reflective plate and the second reflective plate, and are disposed opposite to each other. A long side of the first reflective plate is not equal to a long side of the second reflective plate. A short side at the light output end of at least one of the first reflective plate and the second reflective plate is separate from a short side of the third reflective plate and a short side of the fourth reflective plate at the light output end.