Beam Splitter Module Polarization Alignment
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Solution Overview
Problem
Existing digital light-processing projection apparatuses experience light loss due to mismatched polarization directions of split polarized lights during combining, leading to reduced image intensity and quality.
Innovation Solution
A beam splitter module with a beam splitter element and an optical combiner module comprising prisms and pared-corners, where the polarization direction of each color light is aligned to match during splitting and combining, preventing light loss by ensuring equal image plane directions for S-polarized and P-polarized lights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional beam splitter and combiner configurations are used, then the apparatus structure is simple, but light loss occurs due to polarization direction mismatch
Solution Approach 1:
The optical system is segmented into distinct functional modules: beam splitter module with dedicated beam splitter element, optical combiner module with combiner element, and TIR prism module. Each module handles specific optical functions independently, allowing optimization of polarization control in the beam splitter and combiner without complicating the overall structure.
Solution Approach 2:
The patent introduces polarization control elements (beam splitter element and combiner element) as intermediaries between the light source and the optical path. These intermediaries actively manage the polarization states of color lights, ensuring proper alignment during combining while maintaining structural simplicity through modular design.
2Illumination intensity
If polarization directions are not aligned during light combining, then the optical path is simple, but image intensity and quality are reduced
Solution Approach 1:
The beam splitter element and combiner element are designed with specific polarization-selective properties tailored to their local functions. The beam splitter element selectively splits light based on polarization direction, while the combiner element is configured to combine lights with matched polarization directions. This localized optimization of optical properties ensures high image intensity without requiring complex overall optical path arrangements.
3Productivity
If conventional optical combiner design is used, then the design is straightforward, but light loss reduces productivity
Solution Approach 1:
The beam splitter element performs preliminary polarization separation of color lights before they enter the optical combiner module. By pre-aligning the polarization directions of split color lights, the subsequent combining process becomes more efficient with minimal light loss, thereby improving projection efficiency without requiring overly complex combiner design.
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 ensures no light loss during image projection, enhancing image quality and allowing for a more compact apparatus design, improving market competitiveness.
Implementation Method 1
Dichroic mirrors 402, 404 split colour lights R, G and colour light B, respectively
Implementation Method 2
Curve S1 represents the spectrum of S-polarized light when the incident angle of colour light R is 45 degrees. Curve P1 represents the spectrum of P-polarized light when the incident angle of colour light R is 45 degrees
Implementation Method 3
Colour light B is reflected onto incident plane 242a, while colour light G is reflected onto incident plane 232a. Colour light R, G, B are reflected onto the respective DMDs 500R, 500G, 500B by respective air gaps in Total Internal Reflection (TIR) prisms
Data Source
AI summary
A digital light-processing projection apparatus includes a light source, a beam splitter module and an optical combiner module. The beam splitter module is used in conjunction with an optical combiner module that includes combiners and a plurality of prisms. The beam splitter module comprises a beam splitter element for splitting the beam into a plurality of color lights that pass through the respective prisms separately. The polarization direction of each color light when separated in the beam splitter module is equal to the polarization direction of each respective color light when colour combination in the combiner module.