Luminous Module Laser Safety Guide Face
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Solution Overview
Problem
The use of semiconductor laser elements in motor vehicle light modules poses safety concerns due to their monochromatic coherent light beams, which can be harmful if directly projected onto the road, and requires a photoluminescent element to convert the beam into a broader spectrum for safety, but the precise positioning and sensitivity adjustment of detection devices for wavelength detection are challenging.
Innovation Solution
The light module incorporates a secondary guide face with a greater opening angle in the measurement cone, featuring ridges, facets, or a grained surface to spread light, allowing for increased positioning tolerance and reduced saturation of detection devices, and includes multiple detection devices for redundant light intensity measurement to deactivate the laser when intensity exceeds a safety threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a photoluminescent element is used to convert the laser beam into broader spectrum light, then safety is improved and harmful laser radiation is prevented, but the positioning precision and sensitivity adjustment of detection devices become more challenging
Solution Approach 1:
The reflective surface is divided into two distinct portions: a main portion for forming the outgoing light beam and a secondary guide face for directing measurement light to the detection device. This segmentation allows independent optimization of each function, with the guide face specifically designed to redirect a portion of the emission cone to the detection device, simplifying positioning requirements.
Solution Approach 2:
The reflective surface serves multiple functions: it reflects the majority of light to form the outgoing beam, while a secondary guide face portion redirects a portion of the emission cone to the detection device. This multi-functionality integrates safety monitoring into the existing optical path without requiring separate components, reducing overall system complexity.
2Measurement precision
If the detection device is placed in the measurement cone with a narrow opening angle, then measurement precision is improved, but the positioning tolerance becomes very low and the device is easily saturated
Solution Approach 1:
The guide face is oriented at a specific angle (e.g., 45 degrees) relative to the emission cone, redirecting light from the narrow emission cone into a measurement cone with a larger opening angle. This angular transformation in a different dimensional space allows the detection device to be positioned with greater tolerance while maintaining adequate measurement precision.
Solution Approach 2:
The optical design changes the opening angle parameter of the measurement cone relative to the emission cone. By using the guide face to redirect light, the measurement cone has a larger opening angle than the emission cone, which increases positioning tolerance and reduces saturation risk while maintaining sufficient detection sensitivity through appropriate threshold setting.
3Reliability
If the guide face redirects light to the detection device, then safety monitoring is enabled, but the detection device becomes easily saturated when directly hit by the laser beam
Solution Approach 1:
The guide face extracts only a portion of the emission cone light and redirects it to the detection device, rather than directing the full laser beam intensity. This partial extraction reduces the light intensity reaching the detection device, preventing saturation while maintaining sufficient sensitivity for safety monitoring through appropriate threshold selection.
Solution Approach 2:
The guide face acts as an intermediary optical element between the laser beam and the detection device. It redirects a controlled portion of the light at a specific angle, mediating the interaction to provide adequate detection signal while preventing excessive intensity that would cause saturation. The guide face enables safety monitoring without exposing the detection device to full laser power.
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 design enhances safety by allowing for more flexible positioning and easier adjustment of detection devices, reducing the risk of saturation and ensuring the laser beam is safely deactivated when intensity exceeds safety limits, thereby preventing harmful radiation.
Implementation Method 1
a photoluminescent element configured to convert the wavelength of at least a portion of said laser beam
Implementation Method 2
a reflective surface, a main portion of which reflects light coming from the photoluminescent element to form said outgoing light beam
Implementation Method 3
at least one device for detecting incident light exceeding a predetermined light intensity threshold
Data Source
Figure 1~2
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Figure 7
AI summary
The invention relates to a luminous module (10) comprising: - a semiconductor laser element (12) configured to emit a laser beam (14) in an emission cone (16); - a photoluminescent element (18); - a reflective surface (26) of which a main portion (26A) reflects light from the photoluminescent element (18) to form an outgoing light beam (24); - a secondary guiding face (26B) which reflects the light from the first emission cone (16) into a measurement cone (28); - a device (30) for detecting incident light exceeding a predetermined light intensity threshold which is arranged in the measurement cone (28); characterized in that the optical structure of the guiding face (26B) causes a spreading of the light so that the measurement cone (28) has an opening angle greater than that of the first emission cone (16).