Projection Light Source Layout for Fluorescence Color Separation
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Solution Overview
Problem
In conventional light source devices, part of the excitation light reflected on the phosphor surface returns to the polarization beam splitter as randomly polarized light, leading to mixing and blending with fluorescence, which prevents the output of appropriate colored light.
Innovation Solution
A light source device incorporating a first polarization beam splitter that separates light into different polarization directions and a dichroic mirror that guides reflection light and fluorescence in distinct directions, using a dichroic mirror with an intersecting optical surface to separate and direct light beams effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a polarization beam splitter is used to separate excitation light into different polarization directions, then the directivity of output light is improved, but reflected excitation light mixes with fluorescence causing color contamination
Solution Approach 1:
A dichroic mirror is introduced as an intermediary optical element between the polarization beam splitter and the phosphor. The dichroic mirror selectively reflects fluorescence while transmitting excitation light, preventing the mixing of reflected excitation light with fluorescence and thus eliminating color contamination while maintaining the directivity benefits of the polarization beam splitter.
2Quantity of substance
If excitation light is directed to phosphor for fluorescence generation, then multiple colors of light are produced, but reflected excitation light returns to the optical system causing light of inappropriate color to be output
Solution Approach 1:
The dichroic mirror serves as a selective intermediary that allows excitation light to pass through to generate fluorescence while reflecting the generated fluorescence toward the output. Simultaneously, it blocks reflected excitation light from returning to the optical system, ensuring that only appropriate colored light (fluorescence) is output without contamination from excitation light.
3Device complexity
If a conventional optical path is used without additional separating elements, then the device structure is simple, but fluorescence and reflected excitation light mix and blend
Solution Approach 1:
A dichroic mirror is positioned at a specific angle (45 degrees) relative to the optical axis, creating a compact yet effective separation path. This intermediary element reflects fluorescence at a different angle than the transmitted excitation light, achieving spatial separation of the two light types without significantly increasing device complexity.
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 reduces the mixing of fluorescence and reflected excitation light, ensuring the output of pure colored light by guiding light beams in separate directions, thereby enhancing the quality of projected images.
Implementation Method 1
a first polarization beam splitter that has a first optical surface that separates light incident on the first optical surface into light beams having different polarization directions from each other
Implementation Method 2
a fluorescent emitter that emits fluorescence of a color different from that of the excitation light in response to incident light
Implementation Method 3
the traveling direction of the excitation light is switched by a polarization beam splitter depending on the polarization direction, thereby setting a period when the phosphor is irradiated with the excitation light and emits fluorescence
Implementation Method 4
a dichroic mirror that has a second optical surface, the second optical surface intersecting the first optical surface and guiding reflection light reflected by a fluorescent emitter and fluorescence in different directions from each other
Data Source
AI summary
A light source device includes a first polarization beam splitter and a dichroic mirror. The first polarization beam splitter has a first optical surface that separates light incident on the first optical surface into light beams having different polarization directions from each other. The dichroic mirror has a second optical surface. The second optical surface intersects the first optical surface and guides reflection light reflected by a fluorescent emitter and fluorescence in different directions from each other. The reflection light is part of incident light that has been emitted by a first light source and incident on the fluorescent emitter via the first optical surface. The fluorescence is emitted by the fluorescent emitter in response to the incident light.