Sunlight Imitating Lighting System Homogenization
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Solution Overview
Problem
Lighting systems that imitate natural sunlight struggle to maintain homogeneous luminance and avoid artificiality, particularly in the near field, leading to modulations that can be detected by the eye, affecting the perception of the light source and shadows created.
Innovation Solution
A lighting system comprising an LED-based emitter unit, a compound parabolic concentrator-based collimation unit, and a fly's eye condenser-based homogenization unit, which work together to maintain etendue and provide a continuously emitting output aperture with homogeneous luminance, mimicking the appearance of the sun by reducing luminance modulations and ensuring a sun-like impression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If LED-based light sources with collimating optics are used to imitate sunlight, then the light directionality and beam control are improved, but the luminance homogeneity deteriorates due to shadow effects and modulations
Solution Approach 1:
The patent segments the light source into multiple LED emitters arranged in an array, with each LED having its own collimating optic. This segmentation allows independent control of light beams from each element, enabling the system to maintain directionality while achieving homogeneous luminance through coordinated operation of multiple sources that fill in shadow regions.
Solution Approach 2:
The patent implements a nested structure where collimating optics (lenses or reflectors) are integrated directly with each LED emitter, and the entire LED array is positioned within a housing that provides additional optical control. This nesting allows compact arrangement while maintaining the functional separation needed for both directionality and luminance homogeneity.
2Ease of operation
If collimating optics such as lenses and mirror systems are used with LED sources, then the beam control and light direction are improved, but the device complexity increases
Solution Approach 1:
The patent merges the LED emitter and collimating optic into integrated units, where each LED is paired with its own lens or reflector. This combination simplifies the overall system architecture by eliminating the need for separate, complex optical assemblies, while still providing effective beam control through the distributed array of integrated units.
Solution Approach 2:
Each LED-emitter-optic unit is designed to be self-contained and self-aligning, where the collimating optic is positioned to work optimally with its specific LED emitter. This self-service design reduces the need for complex alignment mechanisms and adjustment procedures, thereby simplifying the overall system while maintaining beam control capability.
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 maintains homogeneous luminance across the beam, reducing detectable modulations and enhancing the natural appearance of the light source, thereby improving the realism of sunlight imitation and reducing the visibility of the light source itself.
Implementation Method 1
a collimation unit, downstream of the emitting unit, the collimation unit being based on compound parabolic concentrators and configured to collimate light emitted by the light source
Implementation Method 2
a homogenization unit, downstream of the collimation unit, the homogenization unit being based on a fly's eye condenser and configured to homogenize the light beam
Implementation Method 3
the panel receives the light from the light source and acts as a so-called Rayleigh diffuser, namely it diffuses light rays similarly to the earth atmosphere in clear-sky conditions
Data Source
Figure 1~2
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AI summary
A lighting system (1) comprises a light source (2) for providing a light beam (3) of directed non-diffused light along a main light beam direction (4). The light source (2) comprises a light emitting unit (100) with a light emission pattern, and an optical system (2A) for receiving and collimating light. The optical system (2A) comprises a collimation unit (200) comprising at least one parabolic interface (220, 230), and a homogenization unit (300) for homogenizing the light emerging from the collimation unit (200). The lighting system (1) comprises further a window-like unit (6) configured as a diffused light generator (20) for generating diffused light.