Fresnel Lens Plate for Compact Vehicle Optical Sensors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical sensor devices for vehicles, such as rain and light sensors, face challenges in minimizing packaging space while maintaining optimal optical performance, with classical lenses requiring large spaces and holographic structures offering reduced light yield and increased sensitivity to extraneous light.
Innovation Solution
The optical sensor device incorporates a lens plate with Fresnel lens and reflector structures, where all optically active elements are concentrated within the plate, allowing for minimal packaging and efficient light transmission and detection, with Fresnel lens structures on one surface and Fresnel reflector structures on the opposite surface, enabling parallel light alignment and total reflection for focused light reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If classical lenses are used for influencing the optical path, then optimal optical performance is achieved, but packaging space increases
Solution Approach 1:
The lens plate is segmented into multiple functional zones: Fresnel lens structures on one surface for light focusing and collimation, and Fresnel reflector structures on the opposite surface for light redirection. This segmentation allows each zone to perform its specific optical function efficiently, achieving optimal optical performance while maintaining a compact overall structure that minimizes packaging space.
2Volume of stationary object
If holographic structures are used to reduce packaging space, then packaging space is minimized, but light yield decreases and sensitivity to extraneous light increases
Solution Approach 1:
The invention changes the optical parameters by using Fresnel lens and reflector structures instead of holographic diffraction elements. The Fresnel lens structures have higher light transmission efficiency and better control over light paths, thereby increasing useful light yield and reducing sensitivity to extraneous light, while still maintaining minimized packaging space through the compact lens plate design.
3Ease of manufacture
If light guide surfaces are arranged perpendicular to the window pane, then optical coupling is simplified, but packaging space increases
Solution Approach 1:
The invention transitions from a three-dimensional arrangement with light guide surfaces perpendicular to the window pane to a two-dimensional planar configuration within the lens plate. The Fresnel lens and reflector structures are integrated into a single planar element that couples light at oblique angles to the window pane, simplifying the optical path while minimizing packaging space through the flat, compact design.
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 configuration minimizes packaging size while achieving a large useful sensor surface and excellent directivity, effectively addressing the limitations of previous technologies by concentrating all optically active elements in the lens plate and optimizing light transmission.
Implementation Method 1
the beam of light emerging from the light transmitter is aligned in parallel by the one Fresnel lens structure
Implementation Method 2
is directed obliquely against the window pane by the corresponding Fresnel reflector structure
Implementation Method 3
totally reflected by the window pane
Implementation Method 4
perpendicularly directed through the lens plate onto the other Fresnel lens structure and thereby concentrated on the light receiver
Data Source
AI summary
An optical sensor device has a sensor unit, which includes a light transmitter, a light receiver and a lens plate, with which a beam of light emitted by the light transmitter is coupled into the window pane, coupled out of the window pane and directed onto the light receiver. On its surface facing the light transmitter and the light receiver, the lens plate includes Fresnel lens structures, and on the opposite surface facing the window pane it includes Fresnel reflector structures. This embodiment is particularly useful as rain sensor. Without light transmitter, the sensor device can be used as a light sensor.