Optoelectronic Sensor Filter Zones for Angle-Dependent Light Suppression
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Solution Overview
Problem
Existing optoelectronic sensors struggle to efficiently suppress extraneous light across varying angles of incidence, leading to significant loss of useful light, especially in bright environments or large measurement distances.
Innovation Solution
The sensor employs an optical filter element divided into multiple filter zones, each adapted to the angle of incidence of partial light beams, ensuring a narrow passband for the useful light spectrum by shifting passbands to match varying angles, thereby effectively filtering out extraneous light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a narrow passband filter is used to suppress extraneous light, then extraneous light suppression is improved, but useful light transmission deteriorates due to angle of incidence variations
Solution Approach 1:
The filter element is divided into multiple filter zones with different passbands, each zone handling a specific angular range of incident light. This segmentation allows the system to maintain narrow effective passbands for extraneous light suppression while accommodating the full angular distribution of useful light through multiple specialized zones.
Solution Approach 2:
Different regions of the filter element are assigned different optical properties (different passbands) according to the local angle of incidence characteristics. Each filter zone is optimized for its specific angular range, creating local quality variations that collectively solve the global problem of angle-dependent light transmission.
2Loss of energy
If a wide passband filter is used to accommodate different angles of incidence, then useful light transmission is improved, but extraneous light suppression deteriorates
Solution Approach 1:
Instead of using a single wide passband filter, the filter element is segmented into multiple zones, each with a narrower passband tailored to a specific angular range. This segmentation enables effective extraneous light suppression in each zone while collectively maintaining high useful light transmission across all angles.
Solution Approach 2:
Each filter zone is designed with local quality optimized for its specific angular range, creating a spatially varying filter response that matches the angular distribution of incident light. This local optimization allows narrow effective passbands without sacrificing overall useful light transmission.
3Adaptability or versatility
If the passband is designed with a margin to tolerate different angles of incidence, then angle tolerance is improved, but extraneous light suppression deteriorates
Solution Approach 1:
The filter element is divided into multiple filter zones, each optimized for a specific angular range without requiring angle tolerance margins. This segmentation eliminates the need for conservative wide passbands while maintaining robust performance across the full angular distribution of incident light.
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 approach allows for efficient suppression of extraneous light without requiring additional measures for angle compensation, enabling the use of a smaller, less costly filter element and maintaining high sensitivity to useful light across different angles of incidence.
Implementation Method 1
An optical filter element is provided as part of the receiving optics system... The filter element is tuned to a useful light wavelength range and thus ensures that, if possible, only received light in the useful light wavelength range hits the light receiver and extraneous light is absorbed or deflected.
Implementation Method 2
A light receiver (36) is provided, which generates a received signal from incident received light (26c).
Implementation Method 3
A receiving optics system is arranged upstream of the light receiver, which performs beam shaping and preferably focusing and preferably has at least one receiving lens for this purpose.
Data Source
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AI summary
An optoelectronic sensor (10) for detecting objects in a surveillance area (22) is specified, which sensor has a light receiver (36) for generating a received signal from received light (26) from the surveillance area (22), a receiving optics (28) for directing the received light (26) onto the light receiver (36) with an optical filter element (34, 35) tuned to a useful light wavelength range for suppressing extraneous light and a control and evaluation unit (48) for detecting information about objects in the surveillance area (22) based on the received signal. The optical filter element (34, 35) comprises at least two filter zones (34a-b, 35a-b), and a respective filter zone (34a-b, 35a-b) is individually adapted to the angle of incidence of a partial light beam of the received light (26) onto the filter zone (34a-b, 35a-b) in its tuning to the useful light wavelength range.