Reflecting Collimators for Homogeneous LED Light Distribution
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Solution Overview
Problem
Existing lighting systems using Lambertian light sources, such as LEDs, suffer from significant light loss and aberrations due to field curvature in projection systems, leading to inefficient light distribution patterns, especially in automotive head lighting and other applications.
Innovation Solution
The use of collimators with reflecting walls instead of refractive lenses allows for efficient light direction into the projection system, minimizing light loss and aberrations, enabling a continuous and homogeneous light distribution pattern in the target area, even when using Lambertian light sources like LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Lambertian light sources (LEDs) are used in the optical system, then the light distribution pattern can be adjusted, but a great part of the emitted light cannot be captured by the micro-lens and is lost
Solution Approach 1:
The optical system is segmented into multiple independent light emitter units, each with its own micro-lens. This allows selective capture and direction of light from each Lambertian source, improving overall light utilization efficiency while maintaining the ability to adjust light distribution patterns across different segments of the illumination area.
2Power
If a projection system with a non planar focal field is used, then light can be focused along a curved focal line, but field curvature causes aberrations and reduces image quality
Solution Approach 1:
Each micro-lens is individually positioned and configured to match the local curvature requirements of the non planar focal field. This allows the system to maintain sharp focus across the curved focal line while compensating for field curvature aberrations, achieving both strong light focusing capability and high image quality.
3Manufacturing precision
If micro-lenses are positioned at a separation distance from the light emitters, then the non planar focal field can be compensated, but the system complexity increases
Solution Approach 1:
The micro-lens array is integrated with the light emitter array in a unified structure, where each micro-lens is directly associated with its corresponding light emitter. This merging of functions reduces system complexity while maintaining the ability to compensate for non planar focal fields through precise positioning and separation distance control.
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 solution ensures a sharp, aberration-free image of the light source unit with a more homogeneous light intensity pattern in the target area, effectively addressing the inefficiencies of previous systems by directing light emitted by LEDs with high efficiency, especially in automotive head lighting applications.
Implementation Method 1
The use of collimators with reflecting walls instead of refractive lenses allows for efficient light direction into the projection system
Implementation Method 2
Lambertian light sources (i.e. light sources having a pattern of the radiated light intensity which is substantially proportional to the cosine of the angle between an observer and a centerline or surface normal in which the light source lies)
Data Source
AI summary
A lighting system is disclosed comprising a light source unit(1) and a projection system(2) for producing a desired light distribution pattern in a target area, especially for use in an automotive head lighting, studio and theatre lighting, indoor spots with adjustable beam width or direction, architectural dynamic lighting, disco lighting and other. The lighting system is especially suitable for a light source unit (1) having one or a plurality of Lambertian light sources(11), especially a plurality of LEDs. For generating a desired light distribution pattern in the target area, the light source unit(1) comprises a plurality of collimators (12) which are dimensioned and/or arranged especially such that the curved focal plane (P) of the projection system(2) intersects with or tangentially touches the exit apertures of the collimators (12).