Rotating DMD Prism for Compact Color Separation
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Solution Overview
Problem
Conventional image projection apparatuses face challenges in miniaturizing the color separation prism due to the need for a proper optical path for OFF light, which increases the prism size and leads to longer back focus and potential interference with other components, limiting the miniaturization of the projector.
Innovation Solution
A color separation and combination system that uses a prism optical system with specific optical planes to guide light from a light source to mirror reflection type image display elements, allowing for the combination of light and proper processing of OFF light without requiring additional space, thus enabling a smaller color separation prism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a proper optical path is configured to guide OFF light to the absorber in the prism, then the OFF light can be properly processed, but the size of the prism increases and the back focus of the projection optical system becomes longer
Solution Approach 1:
The patent changes the spatial arrangement by rotating the DMD relative to the prism, utilizing a different dimensional configuration to guide OFF light. This rotation allows the optical path to be established in a different spatial orientation, avoiding the need to increase prism size in conventional dimensions while still achieving proper OFF light guidance to the absorber.
Solution Approach 2:
The patent introduces a rotatable DMD mechanism that can dynamically adjust its orientation relative to the prism. This dynamic adjustment capability allows the system to optimize the optical path for OFF light without requiring a fixed, large prism structure, thereby reducing the overall prism size while maintaining effective OFF light processing.
2Length of stationary object
If the DMD is rotated relative to the prism to narrow the distance between ON light and OFF light, then the prism width is reduced, but the optical path configuration becomes more complex
Solution Approach 1:
The patent employs a rotatable DMD that can be dynamically positioned at specific angles relative to the prism. This dynamic rotation mechanism simplifies the overall optical path configuration by using a single adjustable component rather than multiple fixed optical elements, thereby reducing prism width while avoiding excessive complexity.
3Stability of the object's composition
If the image display element is separated from the prism to avoid interference, then component interference is avoided, but the back focus of the projection optical system becomes longer
Solution Approach 1:
The patent resolves component interference issues by rotating the DMD in a different spatial dimension relative to the prism, rather than separating components along the optical axis. This dimensional change allows components to be positioned closer together in space while avoiding interference through angular separation, thereby maintaining a short back focus.
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
This configuration allows for a more compact color separation prism, reducing the back focus of the projection optical system and avoiding interference with other components, while effectively processing OFF light without the need for extra optical paths, thereby enhancing the projector's miniaturization and cooling performance.
Implementation Method 1
The third optical plane totally reflects the first color light toward the first image display element, and totally reflects light from the first image display element toward the projection optical system
Implementation Method 2
The fourth optical plane totally reflects the second color light toward the second image display element, and totally reflects light from the second image display element toward the projection optical system
Data Source
AI summary
A color separation and combination system includes a first optical system including a first optical plane, and a second optical system including second to fourth optical planes. The first optical plane guides light from a light source to the second optical plane. The second optical plane guides first color light among light from the first optical plane to the third optical plane, and guides second color light among the light from the first optical plane. The third optical plane totally reflects the first color light toward the first image display element, and totally reflects light from the first image display element toward the projection optical system. The fourth optical plane totally reflects the second color light toward the second image display element, and totally reflects light from the second image display element toward the projection optical system.