Speckle Reducing Device Using Polarization Splitter and Folded Optical Paths
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Solution Overview
Problem
Existing speckle reducing devices face challenges in miniaturization, making it difficult to provide a compact unit while maintaining the required optical path space, which affects the reduction of speckle noise in laser illumination systems.
Innovation Solution
A speckle reducing device is designed using a polarization splitter element and reflecting members to create multiple optical path lengths, with light components being converted and re-directed to superimpose speckle patterns, reducing noise contrast by using a combination of polarization beam splitters and quarter wave plates in a multi-stage structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If two PBSs and one return prism are used to achieve two different optical path lengths, then speckle noise reduction is achieved, but the device size increases and compactness is compromised
Solution Approach 1:
The patent merges the functions of multiple PBSs and return prisms into a single integrated optical module. The polarization splitter element combines beam splitting and path separation functions, while the reflecting members and conversion members are arranged in a compact configuration that achieves multiple optical path lengths without requiring separate discrete components for each function.
Solution Approach 2:
The optical components are nested within a compact arrangement where the first and second reflecting members, along with conversion members, are positioned to create folded optical paths. This nesting allows the light to traverse extended optical path lengths within a reduced physical footprint, effectively hiding the optical paths inside the compact device structure.
2Volume of moving object
If a compact unit is designed, then device size is reduced, but it becomes difficult to assure the required optical path space for speckle reduction
Solution Approach 1:
The patent utilizes three-dimensional spatial arrangement and folded optical paths to extend the effective optical path length within a compact volume. By arranging reflecting members and conversion members in multiple dimensions and using non-linear light paths, the device accommodates sufficient optical path space for speckle reduction while maintaining a small external footprint.
Solution Approach 2:
The optical design employs flexible light routing through multiple reflecting and converting members that can adaptively direct light through different path lengths. This dynamic optical configuration allows the system to achieve variable optical path differences necessary for speckle reduction within the constrained physical space of a compact device.
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 effectively reduces speckle noise contrast to a minimum, allowing for the creation of a compact speckle reducing device that can be integrated into laser illumination systems, enhancing the uniformity of illumination and reducing angular spreading of polarized light components.
Implementation Method 1
a polarization splitter element equipped with a polarization splitter portion that splits incident light into first light containing a first component and second light containing a second component, which outputs the first light and the second light along different directions
Implementation Method 2
a first reflecting member that reflects the first light output from the polarization splitter element, thereby directing the first light to reenter the polarization splitter element
Implementation Method 3
a first conversion member disposed between the first reflecting member and the polarization splitter element, which converts the first light having been reflected by the first reflecting member to third light containing the second component
Data Source
AI summary
A speckle reducing device includes: a polarization splitter element with a polarization splitter portion that splits incident light into first and second light containing a first and a second component respectively, which outputs the first and the second light along different directions; a first reflecting member that reflects the first light to reenter the polarization splitter element; a first conversion member disposed between the first reflecting member and the polarization splitter element, which converts the first light to third light containing the second component; a second reflecting member that reflects the third light to reenter the polarization splitter element; and a second conversion member disposed between the second reflecting member and the polarization splitter element, which converts the third light to fourth light containing the first component, wherein: the polarization splitter element outputs the second and the fourth light along one direction.