Laser Illumination Optics Using Superimposed Images for Uniform Spots
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Solution Overview
Problem
Existing adaptive headlamps using laser diodes experience intensity variations in the laser spot due to multimode characteristics, leading to stripe patterns, which are difficult to homogenize without enlarging the laser spot size.
Innovation Solution
A reflective member with a combination of mirror and prismatic structures is used to superimpose mirror-inverted and non-mirror-inverted images of the laser emitting face on the wavelength converting member, reducing intensity fluctuations without enlarging the laser spot size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If homogenizers are used in the beam path to homogenize intensity variations, then intensity uniformity is improved, but the laser spot size is enlarged
Solution Approach 1:
The reflective member is divided into multiple reflective elements (first and second reflective elements) that separately image different portions of the emitting face. Each element creates a separate image that is then superimposed, achieving homogenization through segmentation rather than using a homogenizer that would enlarge the spot.
Solution Approach 2:
Multiple images of the emitting face are created by different reflective elements and superimposed on the converter. This copying and superimposition approach homogenizes the intensity distribution without requiring physical homogenizers that would increase spot size.
2Manufacturing precision
If the laser spot size is reduced to achieve sharply bounded illumination pattern, then illumination precision is improved, but intensity variations become more pronounced
Solution Approach 1:
The reflective member segments the imaging function into multiple reflective elements, each contributing a separate image. This segmentation allows the system to maintain a small spot size for precision while the combined effect of multiple images reduces intensity variations.
Solution Approach 2:
Multiple images from different reflective elements are merged and superimposed on the converter. This combining approach maintains the small spot size required for sharp boundaries while the superposition of multiple images homogenizes the intensity distribution.
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 proposed solution effectively reduces intensity variations in the laser spot by superimposing images, resulting in a more uniform illumination pattern without increasing the spot size, enhancing the adaptive headlamp's performance.
Implementation Method 1
a wavelength converting member (5) converting at least part of the light of the first wavelength or wavelength range into light of a second wavelength or wavelength range
Implementation Method 2
the laser beam is guided via reflection at a reflective member (3) to the wavelength converting member (5)
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5B
AI summary
An illumination device comprises at least a laser (1) emitting a laser beam (6) of light of a first wavelength, a wavelength converting member (5) converting at least part of the light of the first wavelength into light of a second wavelength, a scanning unit (4) adapted to scan the laser beam (6) across the wavelength converting member (5) and an imaging optics (2) imaging a light emitting face of the laser (1) via the scanning unit (4) onto the wavelength converting member (5). In the proposed device, the laser beam (6) is guided via reflection at a reflective member (3) to the wavelength converting member (5). The reflective member (3) comprises a combination of at least a first and a second reflective element (8, 9), wherein the first and second reflective elements (8, 9) are formed and arranged such that the light emitting face of the laser (1) is imaged as a mirror-inverted image on the wavelength converting member (5) via the first reflective element (8) and as a non-mirror-inverted image via the second reflective element (9), both images being superimposed on the wavelength converting member (5). Due to this reflective member, intensity fluctuations in the image of the light emitting face on the wavelength converting member are reduced without enlarging the image.