Ambient Light Sensor Lens with Total Internal Reflection
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Solution Overview
Problem
Existing electro-optical assemblies for ambient light detection in vehicles face challenges in effectively blocking stray light from unwanted angular ranges, which interferes with the measurement of ambient light, requiring complex manufacturing processes to make parts nontransparent.
Innovation Solution
An electro-optical assembly utilizing a lens body with a depression that employs total internal reflection, where the converging lens section is designed to reflect rays back, preventing light from certain angular ranges from reaching the light receiver, eliminating the need for making parts nontransparent and simplifying manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the depression is made nontransparent by applying a nontransparent film to block stray light, then stray light SS cannot reach the light receiver 6, but the manufacturing process becomes complicated
Solution Approach 1:
The patent replaces the mechanical/optical approach of applying nontransparent films with an electromagnetic approach using circularly polarized light. The reflection layer with specific magnetic properties selectively reflects circularly polarized light while allowing linearly polarized light to pass through, eliminating the need for complex film application processes and achieving stray light blocking through optical polarization properties
Solution Approach 2:
The patent changes the optical parameters of the reflection layer by controlling its magnetic properties and orientation. By adjusting the magnetic saturation and orientation of the reflection layer, the system can selectively reflect or transmit light based on polarization state, providing a controllable and adjustable solution that simplifies manufacturing while maintaining effective stray light blocking
2Adaptability or versatility
If additional depressions 9 are provided in the lens body 4 for rain sensor function, then the lens can serve multiple functions, but stray light SS is refracted and reaches the light receiver 6, impairing measurement
Solution Approach 1:
The patent replaces the geometric/optical blocking approach with an electromagnetic polarization-based approach. The circularly polarized light combined with the magnetically controlled reflection layer creates a selective filtering mechanism that can distinguish between light from different angular ranges based on polarization state, allowing the same optical path to serve both ambient light sensing and rain detection functions without mutual interference
Solution Approach 2:
The patent uses a composite structure combining the lens body material with a magnetically active reflection layer. This composite material system provides both the optical focusing/refraction properties of the lens material and the selective electromagnetic reflection properties of the magnetic layer, enabling multi-functionality while preventing stray light interference through the unique polarization-selective properties of the composite structure
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 effectively blocks stray light from reaching the light receiver, improving the accuracy of ambient light detection without the complexity of making parts nontransparent, allowing for a compact and efficient design that can be integrated into vehicles.
Implementation Method 1
the interior wall of the converging lens section is formed in such a way that the rays of the ray path which travel through the converging lens section to the electro-optical component hit the reflection surface in such way that the angle of incidence at the reflection surface is larger or equal to the critical angle of the total internal reflection at the reflection surface
Implementation Method 2
The depression comprises a main lens section, in particular a diverging lens section with a concave interior wall, and a converging lens section with a convex interior wall
Data Source
AI summary
An electro-optical assembly, in particular a sensor assembly for detecting ambient light, includes a reflection surface, a lens body and an electro-optical component, in particular a light receiver. The component includes a depression having a main lens section, in particular a diverging lens section with a concave interior wall, and a converging lens section with a convex interior wall. The interior wall of the converging lens section is formed in such a way that the rays of the ray path which travel through the converging lens section to the electro-optical component hit the reflection surface in such way that the angle of incidence at the reflection surface is larger or the same as the critical angle of the total internal reflection at the reflection surface. In another aspect a method for detecting ambient light is described.