Compact Beam Combiner Using Brewster Angle Incidence
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Solution Overview
Problem
Conventional RGB beam combiners, used in projectors, are bulky due to their construction with multiple prisms, making them unsuitable for smaller and lighter projector designs required for portability in applications like seminars and video conferences.
Innovation Solution
A compact beam combiner design utilizing two lenses with specific beam-splitting films and Brewster's angle incidence, allowing for the combination of three color light beams in a single path, reducing the device's size and manufacturing cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional RGB beam combiner uses four prisms to combine color light beams, then the beam combining function is achieved, but the device size becomes large and unsuitable for portable projectors
Solution Approach 1:
The patent segments the beam combining function into two separate beam splitters (first and second beam splitters) with specific optical orientations, replacing the conventional four-prism structure. This segmentation allows each component to handle specific color beam combinations, achieving the same functional result with reduced overall size and complexity.
Solution Approach 2:
The patent introduces a specific spatial arrangement where the first and second beam splitters are positioned at perpendicular orientations (90 degrees to each other), creating a compact L-shaped optical path. This dimensional arrangement allows three color light beams to be combined in a smaller volume by utilizing orthogonal spatial relationships rather than sequential linear arrangement.
2Volume of moving object
If beam combiner is reduced in size for portability, then device compactness is improved, but the optical path space for three different direction beams is insufficient
Solution Approach 1:
The patent utilizes perpendicular spatial arrangement of beam splitters to accommodate multiple optical paths in a compact volume. The first beam splitter handles horizontal beam combinations while the second beam splitter handles vertical beam combinations, effectively using three-dimensional spatial relationships to resolve the conflict between compactness and optical path requirements.
Solution Approach 2:
The patent employs asymmetric optical path design where different color beams enter and exit through different surfaces of the beam splitters at specific angles. This asymmetric arrangement optimizes the use of available space within the compact device, allowing efficient light beam routing without requiring symmetric expansion of the device volume.
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 enables the combination of RGB light beams in a smaller, more portable form factor without the need for multiple prisms, achieving efficient light combination and cost-effective manufacturing.
Implementation Method 1
a first beam-splitting film, a second beam-splitting film... the first beam-splitting film allows the first color light beam to transmit through and reflects the second color light beam, and the second beam-splitting film allows the third color light beam to transmit through and reflects the first light beam and the second color light beam
Implementation Method 2
an included angle between the first incidence surface and the second incidence surface is ninety degrees minus Brewster's angle, the first color light beam enters the first lens via the first incidence surface with an incidence angle of Brewster's angle
Data Source
AI summary
A beam combiner includes a first lens and a second lens coated with specific optical films. The first color light beam enters the first lens via a first incidence surface with an incidence angle of Brewster's angle. The second color light beam enters the first lens via the second incidence surface with an incidence angle of zero degree. The third color light beam enters the second lens via the third incidence surface with an incidence angle of zero degree. The first, the second, and the third color light beams transmit in the same path after the splitting face to form the composite light beam and come out via an exit surface.