Anamorphic Optics for Homogeneous Line Scan Illumination
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Solution Overview
Problem
Optoelectronic sensors with simple lighting arrangements suffer from low light efficiency due to unshaped light emission, and those with beam-shaping elements face challenges in achieving homogeneous illumination profiles, especially when the light-emitting diodes and receiving lens are in the same plane, leading to inhomogeneous lighting and edge drop issues.
Innovation Solution
The use of anamorphic imaging optics with off-axis aligned light-emitting diodes, condenser elements, and cylindrical lenses, where the vertex distance and wedge angles are adjusted to control the main beam direction, allowing for targeted illumination profiles and increased light coupling efficiency, enabling the generation of specific lighting profiles and compensating for edge drop effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If beam-shaping elements are added to concentrate light onto the detection area, then light efficiency is improved, but the lighting profile becomes inhomogeneous
Solution Approach 1:
The patent applies local quality by varying the off-axis alignment of individual light-emitting diodes based on their position in the array. Diodes at different locations have different alignment angles relative to the receiving lens optical axis, creating locally optimized illumination that compensates for position-dependent effects like edge drop, thereby achieving homogeneous overall illumination while maintaining high light efficiency
Solution Approach 2:
The patent implements dynamics by making the off-axis alignment angle a variable parameter that changes depending on the distance from the receiving optics and the position of each LED. This dynamic adjustment of alignment angles allows the system to adapt the illumination profile to different operating conditions and detection area distances, resolving the contradiction between concentration and homogeneity
2Length of stationary object
If light-emitting diodes and receiving lens are positioned in the same plane to reduce depth of field, then device compactness is improved, but lighting profile homogeneity deteriorates
Solution Approach 1:
The patent resolves this contradiction by applying local quality through position-dependent off-axis alignment. Each LED's alignment angle is specifically tailored to its location in the array and its distance from the receiving lens, compensating for the inhomogeneities introduced by the coplanar configuration. This allows compact depth of field while maintaining homogeneous illumination through localized optimization
3Illumination intensity
If off-axis alignment is increased to compensate for edge drop, then lighting profile homogeneity is improved, but light coupling efficiency into condenser element decreases
Solution Approach 1:
The patent applies dynamics by making the off-axis alignment angle a dynamic parameter that varies continuously based on position and distance. Rather than using a fixed large angle that would reduce coupling efficiency, the system dynamically adjusts each LED's alignment angle to the optimal value for its specific location, thereby achieving edge drop compensation while maintaining high light coupling efficiency into the condenser element
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 enhances light efficiency and homogeneity in the illumination profile, allowing for optimized light distribution and the ability to create tailored illumination patterns, even at varying distances and detection area sizes, while maintaining economic viability by using identical condenser elements with adjustable configurations.
Implementation Method 1
The beam-shaping elements are parts of anamorphic imaging optics, in which each light-emitting diode is assigned a condenser element of the same design and a cylindrical lens
Implementation Method 2
each light-emitting diode is assigned a condenser element of the same design and a cylindrical lens
Data Source
Figure 1~2
Figure 3
Figure 4~5b
AI summary
The invention relates to an optoelectronic sensor (1), in particular a line scan camera, with a receiving optic (2) and an arrangement of several light-emitting diodes (LEDs) aligned in a line, mounted in the region of the receiving optic for illuminating a detection area (3) with an anamorphic imaging optic, wherein each LED (LED) is associated firstly with a beam-shaping optical condenser element (4i) and secondly with a cylindrical lens (5). In order to generate a very specific illumination profile in the detection area of the optoelectronic sensor (1), it is provided that the LEDs have a different off-axis orientation (x) to the optical axis of the condenser elements with increasing distance from the receiving optic and/or that the vertex distance (s) between the condenser element and the cylindrical lens also changes depending on the distance to the receiving optic (2).