Laser Light Source Device Speckle Reduction via Fluorescence Conversion
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Solution Overview
Problem
The existing projection systems using laser light sources suffer from a speckle effect due to high coherence, resulting in poor display effects with granular bright and dark spots on the projection image.
Innovation Solution
A light source device comprising a first laser light source group, a second laser light source group, a dichroic mirror, a fluorescence converter, and an emission component, which emits laser light of different wavebands and combines them with fluorescence to reduce coherence and improve image display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If laser light source is used in projection system, then brightness and purity of light are improved, but speckle effect occurs due to high coherence causing poor display effect
Solution Approach 1:
The patent segments the monochromatic laser light into multiple wavelength bands using a diffraction grating, creating several separated light beams with different wavelengths. This segmentation reduces the temporal coherence of the light while maintaining spatial coherence, thereby reducing the speckle effect while preserving brightness for projection display.
Solution Approach 2:
The patent changes the wavelength parameter of the light by using a diffraction grating to separate the laser light into multiple wavelength components. This parameter change transforms the single-wavelength coherent light into multi-wavelength light with reduced coherence, effectively mitigating the speckle effect while maintaining illumination intensity.
2Productivity
If laser light of three colors is directly combined and modulated, then projection image is formed, but speckle effect reduces image quality
Solution Approach 1:
The patent applies segmentation by dividing each color laser beam into multiple wavelength bands using diffraction gratings. This creates multiple separated light beams per color that can be independently modulated and combined, reducing speckle while maintaining the ability to form projection images through sequential or simultaneous modulation.
Solution Approach 2:
The patent uses periodic action through time-sequential modulation of the multiple wavelength beams. The light source device modulates different wavelength beams in a periodic time sequence, allowing each beam to be processed and combined to form the projection image while reducing coherent interference effects.
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 proposed solution effectively reduces the speckle effect, enhancing the display effect of the projection image by improving luminance and color saturation, and achieving higher definition in the projected images.
Implementation Method 1
the fluorescence converter is capable of generating target fluorescence under excitation of the laser light of the first waveband
Implementation Method 2
the dichroic mirror is configured to emit the laser light of the first waveband, the laser light of the second waveband, and the laser light of the third waveband
Data Source
AI summary
Provided is a light source device, including a first laser light source group, a second laser light source group, a dichroic mirror, a fluorescence converter, and an emission component. The first laser light source group emits laser light of a first waveband, and the second laser light source group emits laser light of a second waveband and laser light of a third waveband. The dichroic mirror is disposed on light-output sides of the first laser light source group and the second laser light source group, and the fluorescence converter and the emission component are respectively disposed on light-output sides of the dichroic mirror. The dichroic mirror is configured to emit laser light of various wavebands, and the fluorescence converter generates target fluorescence under the excitation of the laser light of the first waveband, and the target fluorescence is reflected by the dichroic mirror to the emission component.