Projection Illumination System Speckle Reduction
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Solution Overview
Problem
Laser speckle phenomena caused by coherent laser beams result in non-uniform brightness and degraded image quality in projection devices, and existing diffuser solutions compromise optical efficiency.
Innovation Solution
An illumination system with a coherent light source, multiple optical modules, and strategically positioned diffuser elements with varying haze levels to minimize speckle effects while maintaining optical efficiency, ensuring uniform brightness and high image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the diffusion degree or number of diffuser elements is increased to enhance the diffusing effect, then the laser speckle phenomenon is reduced, but the optical coupling efficiency is reduced
Solution Approach 1:
The patent divides the single diffuser element into multiple diffuser elements (first diffuser element and second diffuser element) arranged in sequence along the optical path. Each diffuser element has different haze parameters, creating a segmented approach to light diffusion that reduces speckle while maintaining optical efficiency
Solution Approach 2:
The patent applies different haze parameters to different diffuser elements based on their positions in the optical path. The first diffuser element has a first haze parameter while the second diffuser element has a second haze parameter that is different from the first, optimizing the diffusing effect at each stage without excessive energy loss
2Object-affected harmful factors
If a diffuser element is arranged at the position where optical paths are concentrated, then the laser speckle phenomenon is alleviated, but the optical efficiency is compromised
Solution Approach 1:
The patent introduces a control unit that can adjust the haze parameters of the diffuser elements dynamically. This allows the system to optimize the balance between speckle reduction and optical efficiency based on different operating conditions, rather than using fixed haze parameters
Solution Approach 2:
The patent changes the haze parameters of the diffuser elements based on their positions in the optical path and different working conditions. The first diffuser element has a first haze parameter while the second diffuser element has a second haze parameter, and these parameters can be adjusted to optimize both speckle reduction and optical efficiency
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 reduces non-uniform intensity distribution and speckle phenomena, achieving uniform brightness and high optical efficiency, thereby enhancing image quality in projection devices.
Implementation Method 1
The coherent beam is focused on a first position through the first optical module
Implementation Method 2
The first diffuser element is located on a transmission path of the coherent beam
Implementation Method 3
The coherent beam is focused on a second position through the second optical module
Implementation Method 4
The second diffuser element is located on a transmission path of the coherent beam from the second optical module
Data Source
AI summary
The invention provides an illumination system and a projection device with the illumination system. The illumination system is configured to provide an illumination beam, and includes a coherent light source, a first and a second optical module, a first and a second diffuser element. A coherent beam emitted by the coherent light source is focused on a first position through the first optical module, and the first diffuser element is located at or near the first position. The coherent beam from the first diffuser element is focused on a second position through the second optical module. The second diffuser element is located on a transmission path of the coherent beam from the second optical module, and located at or near the second position. The coherent beam sequentially passes through the first diffuser element, the second optical module and the second diffuser element to form the illumination beam.