Laser Headlight Optics for Homogeneous Illumination Patterns
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Solution Overview
Problem
Existing laser-based light sources for vehicle headlights face challenges in providing a reproducible and homogeneous light pattern due to variations in angular intensity distribution and positioning sensitivity, especially when using multimode laser diodes with changing operating conditions.
Innovation Solution
A laser-based light source with an optical arrangement that broadens the image of the laser light on a light converter, using overlapping focused images and optical elements like lenses and prisms to achieve a consistent intensity distribution, independent of positioning tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the laser image is focused tightly on the light converter, then the light pattern can be precisely controlled, but the system becomes highly sensitive to positioning errors and manufacturing tolerances
Solution Approach 1:
The patent divides the laser beam into multiple parallel sub-beams using a beam splitter array, where each sub-beam is focused to a separate spot on the light converter. This segmentation allows the system to achieve precise light pattern control through the array configuration rather than relying on a single tight focus, thereby reducing sensitivity to positioning errors in individual beams.
Solution Approach 2:
The patent transitions from controlling light pattern through single-point precise positioning to controlling it through the spatial arrangement of multiple sub-beams in an array. By adding the dimension of multiple parallel beams with controlled spacing, the system achieves both precision and robustness against positioning tolerances.
2Adaptability or versatility
If scanning arrangements are used to move the focused laser image across the light converter, then a customized light pattern can be achieved, but the device complexity increases
Solution Approach 1:
Instead of using a single moving laser spot that scans across the light converter, the patent segments the laser beam into multiple parallel sub-beams that are simultaneously focused to multiple spots. This eliminates the need for mechanical scanning arrangements while still achieving customized light patterns through the static array configuration.
Solution Approach 2:
The patent replaces the mechanical scanning system with an optical beam splitting and parallel focusing system. The beam splitter array and corresponding lens array create multiple focused spots without any moving parts, thereby achieving light pattern customization without mechanical complexity.
3Power
If the laser diode operates in multimode with changing temperature, then the power output can be adjusted, but the angular intensity distribution changes and affects light pattern consistency
Solution Approach 1:
By dividing the laser beam into multiple sub-beams and focusing them to separate spots, the patent makes the overall light pattern less sensitive to angular intensity distribution changes in the source. The array configuration distributes the impact of mode changes across multiple beams, maintaining pattern consistency even when the laser operates in multimode with temperature variations.
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 provides a robust and reliable light pattern with reduced sensitivity to positioning errors, ensuring a homogeneous and reproducible illumination, even under varying operating conditions.
Implementation Method 1
the optical arrangement is adapted to provide a focused image of the laser on a light converter
Implementation Method 2
The optical arrangement is further adapted to broaden the image of the laser on the light converter of the light converting device in at least a first direction
Implementation Method 3
The light converter is adapted to convert laser light to converted light, wherein a peak emission wavelength of the converted light is in a longer wavelength range than a laser peak emission wavelength of the laser light
Data Source
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AI summary
A vehicle headlight has a laser-based light source (100) comprising: • - a laser (110) for emitting laser light, • - a light converting device (130) with a light converter for converting the laser light to converted light with a peak emission wavelength greater than a peak emission wavelength of the laser light, and • - an optical arrangement (150) for providing a transformed focused image (11') of the laser (110) on the light converter, thereby broadening the image (11) in at least a first direction (51) perpendicular to an optical axis (50) of the laser-based light source (100), such broadening being independent from a second direction (52) being perpendicular to the optical axis (50) and to the first direction (51), wherein the optical arrangement (150) is adapted to broaden the image of the laser by providing at least two overlapping images (11a - Ilk) of the laser (110) on the light converter (130) broadened in at least the first direction (51).