Phosphor Wheel Light Source Device with Anisotropic Diffusion
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Solution Overview
Problem
Existing light source devices with phosphor wheels suffer from increased size and optical loss due to the need for multiple optical components to combine excitation and fluorescent light, which are emitted in opposing directions, reducing light use efficiency.
Innovation Solution
A light source device design where diffused excitation and fluorescent light are emitted from the same side of the phosphor wheel, utilizing a mirror with dichroic and wide wavelength transmissive regions to guide and combine these lights without additional optical components, and an anisotropic diffusion and reflection unit to prevent optical path overlap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If excitation light and fluorescent light are emitted in opposing directions through the phosphor wheel, then both lights can be generated, but the number of optical components increases and the device size is enlarged
Solution Approach 1:
The patent merges the optical paths of excitation light and fluorescent light by using a beam splitter that allows both lights to be emitted from the same side of the phosphor wheel. The beam splitter combines the transmitted excitation light and the fluorescent light into a single optical path, eliminating the need for separate optical components for each light direction, thus reducing device complexity while maintaining illumination intensity
Solution Approach 2:
The beam splitter acts as an intermediary optical component that mediates between the excitation light source and the fluorescent light emission. It selectively transmits excitation light while allowing fluorescent light to pass through, enabling both lights to be combined and emitted from the same side without requiring multiple separate optical paths or components
2Illumination intensity
If multiple optical components are disposed in the optical system to combine lights, then excitation and fluorescent light can be combined, but optical loss increases and light use efficiency decreases
Solution Approach 1:
The patent reduces optical loss by merging the optical paths of excitation light and fluorescent light through a beam splitter. This consolidation eliminates the need for multiple separate optical components that would each introduce additional optical losses, thereby improving light use efficiency while maintaining the required illumination intensity
Solution Approach 2:
The beam splitter serves as an efficient intermediary that minimizes optical loss by providing a single optical path for both excitation and fluorescent light. This reduces the cumulative optical losses that would occur with multiple separate components, improving overall light use efficiency while maintaining illumination intensity
3Device complexity
If excitation light optical path and diffused excitation light optical path are overlapped, then the structure is simplified, but optical interference occurs and light quality deteriorates
Solution Approach 1:
The patent applies local quality by making the phosphor wheel anisotropic in its light diffusion properties. The phosphor wheel has different diffusion characteristics for different directions: it diffuses excitation light in one direction while maintaining a clear optical path for transmitted excitation light in another direction. This directional differentiation prevents optical path overlap and interference while maintaining structural simplicity
Solution Approach 2:
The patent introduces asymmetry in the optical path design by using anisotropic diffusion and reflection units in the phosphor wheel. These units create asymmetric light distribution patterns that separate the optical paths of transmitted excitation light and diffused excitation light, preventing overlap and interference while keeping the overall structure simple
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 size of the light source device while maintaining illumination light intensity by eliminating the need for additional optical components and minimizing optical loss.
Implementation Method 1
a phosphor wheel including a phosphor segment configured to generate fluorescent light by excitation of the excitation light from the excitation light source
Implementation Method 2
an anisotropic diffusion and reflection unit configured to diffuse and reflect incident excitation light so that an optical path of the incident excitation light and an optical path of diffused excitation light after the incidence of the excitation light are not overlapped
Implementation Method 3
an anisotropic diffusion and reflection unit configured to diffuse and reflect incident excitation light
Implementation Method 4
the mirror includes a first region configured to reflect the excitation light and transmit the fluorescent light
Implementation Method 5
the mirror includes a first region configured to reflect the excitation light and transmit the fluorescent light, and a second region configured to transmit the fluorescent light and the diffused excitation light
Data Source
AI summary
A light source device includes an excitation light source that generates excitation light, a phosphor wheel including a phosphor segment that generates fluorescent light by excitation of the excitation light, and a mirror that guides the excitation light from the excitation light source to the phosphor wheel and emits the fluorescent light from the phosphor wheel as illumination light. The phosphor wheel further includes an anisotropic diffusion and reflection unit that diffuses and reflects incident excitation light such that an optical path for the incident excitation light and an optical path for the diffused excitation light after incidence of the excitation light are not overlapped. The mirror includes a first region that reflects the excitation light and transmits the fluorescent light and a second region that transmits the fluorescent light and the diffused excitation light which the anisotropic diffusion and reflection unit has diffused and reflected.