Modular Illuminator for Wide Field of View Imaging
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Solution Overview
Problem
Current illumination systems for optical imaging struggle to provide a wide beam with high homogeneity and low etendue, limiting their ability to optimally illuminate large fields of view while maintaining high collection and transmission efficiency.
Innovation Solution
The proposed solution involves a modular illumination system using an array of light sources, catadioptric lenses, cylindrical or spherical lens arrays, and output lenses to collimate and homogenize light, allowing for wide field illumination with high collection and transmission efficiency across the beam's profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional illumination systems are used, then the system structure is simple, but the field of view is limited and homogeneity is poor
Solution Approach 1:
The illumination system is divided into multiple independent optical modules, each containing light sources and optical elements. This segmentation allows each module to cover a specific angular range while maintaining structural simplicity, and multiple modules can be combined to achieve wide field of view illumination without requiring a single complex system
Solution Approach 2:
The patent introduces angular distribution as an additional dimension for light delivery, using catadioptric lenses to illuminate different angular zones. This allows the system to expand the field of view not just by increasing beam width in one direction, but by distributing light across multiple angular dimensions, achieving wide coverage while maintaining compact module design
2Area of stationary object
If beam width is increased to cover wide field of view, then field of view is improved, but beam homogeneity deteriorates
Solution Approach 1:
Different regions of the illumination system are designed with different optical properties. Catadioptric lenses are positioned to deliver light to specific angular zones with optimized intensity distributions, ensuring each local region receives appropriate illumination while the overall system maintains high homogeneity across the wide field of view
Solution Approach 2:
Diffusing elements are introduced as intermediary components between the light sources and the field of view. These diffusers redistribute light intensity to eliminate hot spots and dark regions, maintaining beam homogeneity even when illuminating wide angular ranges, without requiring complex optical alignment
3Loss of energy
If etendue is reduced for efficient light collection, then collection efficiency is improved, but field of view coverage deteriorates
Solution Approach 1:
The light collection system is segmented into multiple catadioptric lenses, each optimized to collect light from a specific angular range with high efficiency. By dividing the wide field of view into multiple zones, each lens maintains a manageable etendue while collectively covering the entire wide angle, preserving both collection efficiency and field of view coverage
Solution Approach 2:
The system exploits angular distribution as an additional dimension to decouple etendue constraints from field of view coverage. By delivering light through multiple angular channels, each with optimized etendue matching, the system achieves wide field of view illumination without sacrificing collection efficiency in any individual channel
4Area of stationary object
If multiple optical elements are added to widen beam, then field of view is improved, but transmission efficiency deteriorates
Solution Approach 1:
Catadioptric lenses are designed to perform multiple functions simultaneously: they collect light from LED sources, shape the beam profile, and deliver light to specific angular zones. This multi-functionality reduces the need for separate optical elements for each function, minimizing the number of interfaces and associated transmission losses while achieving wide field of view coverage
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
This approach enables the illumination of fields exceeding 90 degrees with high homogeneity and efficiency, suitable for various imaging applications, including multi-spectral and hyper-spectral imaging systems, while maintaining a high delivery efficiency.
Implementation Method 1
one or more catadioptric lenses arranged to collect light from the array of light sources
Implementation Method 2
catadioptric lenses
Implementation Method 3
a first array of lenses arranged in a first row that is substantially perpendicular to an optical path of light from the one or more catadioptric lenses
Implementation Method 4
A first optical arrangement is configured to collect the output radiation beams from all of the diode-laser bar stacks, homogenize and expand the beams in the length direction of the line of radiation
Implementation Method 5
an output lens arranged to collect light from the second array of lenses
Data Source
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AI summary
A modular illumination system is capable of producing a light beam having a wide field of view - e.g., in excess of ninety degrees - while maintaining a high collection efficiency as well as a high degree of beam homogeneity. The illumination system comprises an elementary unit (300) having a linear array of light sources (306). Light from the light sources (306) is collimated using a corresponding array of catadioptric lenses (308), and the collimated light is homogenised in the tangential plane using two cylindrical lens arrays (304a, 304b) set in tandem to one another. The homogenised light is then collimated in the sagittal plane using a cylindrical lens (302) that is set perpendicular to the lenses of the two cylindrical lens arrays (304a, 304b) to yield a wide linear beam. To produce an area beam, the linear array of light sources (306) can be replaced with a two-dimensional array, and the cylindrical lenses (304a, 304b) can be replaced with spherical lenses.