Speckle-Suppressing Lighting System Using Waveguide Diffuser
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Laser-based white light for lighting faces challenges such as speckle noise due to coherent light interference, leading to non-uniform light intensity distribution, and existing speckle reduction methods are costly, cumbersome, and unsuitable for next-generation white laser lamps.
Innovation Solution
A speckle-suppressing lighting system utilizing an optical waveguide with a diffuser and multiple solid-state light sources emitting different wavelengths, where the light sources are optically coupled to the waveguide and the diffuser diffuses the light beams to reduce speckle noise without significant efficiency loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If laser-based white light is used for lighting, then efficiency and power density are improved, but speckle noise causes non-uniform light intensity distribution
Solution Approach 1:
The patent segments the coherent laser light into multiple independent spatial modes using an integrating rod, which breaks up the coherent wavefront into many incoherent paths. This segmentation transforms the single coherent beam into multiple scattered beams that recombine to form uniform incoherent light, eliminating speckle while preserving the high efficiency of laser sources.
Solution Approach 2:
The integrating rod acts as an intermediary component between the laser source and the output. It receives coherent laser light, performs multiple internal reflections to scramble the spatial coherence, and outputs incoherent light. This intermediary device mediates the transformation from coherent to incoherent light without significant energy loss.
2Object-affected harmful factors
If conventional speckle reduction methods are used, then speckle noise is reduced, but device complexity and cost increase
Solution Approach 1:
The patent replaces expensive, complex active speckle reduction components (such as deformable mirrors, acousto-optic modulators, or rotating diffusers) with a simple, passive integrating rod. This rod is a low-cost, static optical element that achieves speckle suppression through geometric optics rather than active control, dramatically simplifying the system.
Solution Approach 2:
The patent replaces mechanical or active optical systems (rotating diffraction gratings, deformable mirrors requiring actuators and control systems) with a static integrating rod that uses passive multiple internal reflections. This substitution eliminates moving parts and complex control electronics, reducing device complexity and improving reliability.
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 system effectively suppresses speckle noise below human perception limits while maintaining high efficiency, achieving uniform light distribution and improved color temperature and transmission speed.
Implementation Method 1
The diffuser diffuses the first light beam and the second light beam
Implementation Method 2
an optical waveguide with a diffuser and multiple solid-state light sources emitting different wavelengths, where the light sources are optically coupled to the waveguide and the diffuser diffuses the light beams
Data Source
AI summary
A speckle-suppressing lighting system includes an optical waveguide, a first solid-state light source, a second solid-state light source, and a diffuser. The optical waveguide has a proximal end and a distal end. At least part of the diffuser is between the proximal end and the distal end. The first solid-state light source is optically coupled to the optical waveguide near the proximal end, and emits a first light beam that propagates toward the distal end and has a first center wavelength. The second solid-state light source is optically coupled to the optical waveguide near the proximal end, and emits a second light beam that propagates toward the distal end and has a second center wavelength differing from the first center wavelength. The diffuser diffuses the first light beam and the second light beam.