Laser Light Source Layout for Uniform Projector Illumination
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Solution Overview
Problem
Existing light source devices for display devices, such as projectors, suffer from non-uniform illuminance distribution and speckle formation due to uneven angular diversity of laser wavelengths, which is exacerbated by the use of conventional wavelength multiplexing techniques that fail to adequately average wavelength differences.
Innovation Solution
A light source device configuration with vertically and horizontally flipped arrangements of laser sources of different wavelengths between two modules, utilizing dichroic mirrors and polarization multiplexing to achieve uniform illuminance distribution without additional components like sub-fly-eye lenses, thereby reducing speckles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional wavelength multiplexing techniques are used, then device complexity is reduced, but illuminance distribution uniformity deteriorates and speckles increase
Solution Approach 1:
The light source device is divided into multiple independent laser light sources emitting different wavelengths (first through eighth light sources with first, second, and third peak wavelengths). Each wavelength component is independently controlled and directed through separate optical paths, allowing individual optimization of illuminance distribution for each wavelength band while maintaining overall system uniformity
Solution Approach 2:
The patent employs asymmetric optical path design where different wavelengths follow different trajectories through the system. The first and fifth laser lights pass through the first optical member, while the second and sixth pass through the second optical member, and the third and seventh are reflected by the second optical member, creating asymmetric but balanced illuminance distribution across the display surface
2Device complexity
If conventional wavelength multiplexing techniques are used, then device complexity is reduced, but speckle formation increases
Solution Approach 1:
The system dynamically manages wavelength distribution by independently controlling multiple laser sources at different wavelengths through separate optical paths. This dynamic control allows the system to average out angular diversity across wavelengths, reducing the coherence effects that cause speckle formation while maintaining efficient device architecture
Solution Approach 2:
The patent changes the wavelength parameter across multiple independent light sources (first peak wavelength, second peak wavelength, third peak wavelength) and directs them through different optical paths. This parameter diversification reduces the monochromatic coherence that causes speckles, while the asymmetric optical routing further distributes angular diversity to suppress speckle formation
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 solution provides a light source device with improved uniformity in illuminance distribution and reduced speckles, maintaining device size and cost efficiency by averaging angular diversity of wavelengths without increasing component count.
Implementation Method 1
The first and fifth laser lights pass through the first optical member. The second and sixth laser lights pass through the second optical member. The third and seventh laser lights are reflected by the second optical member. The fourth and eighth laser lights are reflected by the first optical member.
Data Source
AI summary
The light source includes first to eighth light sources configured to emit first to eighth lights, respectively. The first light has a first peak wavelength, the second light has a second peak wavelength, the third light has a third peak wavelength, and the fourth light has the second peak wavelength. The fifth light has the third wavelength, the sixth light has the second wavelength, the seventh light has the first wavelength, and the eighth light has the second wavelength. The first and fifth lights pass through a first optical member. The second and sixth lights pass through a second optical member. The third and seventh lights are reflected by the second optical member. The fourth and eighth lights are reflected by the first optical member.