DPM Scanner Illumination Assembly with Aspheric Lens
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Solution Overview
Problem
Direct part marking scanners face challenges in providing effective illumination for both bright field and dark field scenarios, especially when dealing with irregular surfaces, as conventional light pipes fail to provide sufficient contrast on low reflective or diffused reflective surfaces, and existing solutions do not adequately address the need for both contact and distant illumination options.
Innovation Solution
The illumination assembly features an LED assembly with a continuous aspheric cylindrical lens and a V-shaped LED reflector, which redistributes light to the region of interest, eliminating the need for light pipes and enabling both dark field and bright field illumination at various distances, while allowing for high or low incidence angles, thus simplifying the scanner design and improving LED efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light pipes are used to provide dark field illumination, then low angle illumination is achieved, but sufficient contrast is not provided on low reflective or diffused reflective surfaces
Solution Approach 1:
The patent removes the light pipe component from the illumination assembly and replaces it with LED assemblies positioned to provide both bright field and dark field illumination directly, eliminating the intermediate light pipe structure that failed to provide sufficient contrast
Solution Approach 2:
The patent changes the illumination parameters by using multiple LED assemblies with different orientations (one facing the diffuser, one facing away) to provide both high angle bright field and low angle dark field illumination, achieving sufficient contrast on low reflective surfaces
2Adaptability or versatility
If conventional illumination assemblies are used, then structure is simplified, but both bright field and dark field illumination at various distances cannot be provided
Solution Approach 1:
The patent creates a multi-functional illumination assembly where LED assemblies provide both bright field and dark field illumination at contact and distant ranges, eliminating the need for separate illumination systems for different distances and surface types
Solution Approach 2:
The illumination assembly is segmented into multiple LED assemblies with different orientations and positions, allowing each segment to contribute to different illumination functions (bright field, dark field, contact, distant) that work together to provide comprehensive coverage
3Illumination intensity
If high angle bright field illumination is used, then illumination intensity is improved, but two-dimensional surface texture is not contrasted effectively
Solution Approach 1:
The patent applies different illumination qualities to different needs by using high angle bright field illumination for general brightness and low angle dark field illumination specifically for surface texture contrast, with each LED assembly oriented to provide its specific local function
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 allows for compact, lightweight scanners with improved heat dissipation and longer LED life, providing effective illumination for both bright field and dark field scenarios on irregular surfaces, enhancing image acquisition by offering both contact and distant illumination options.
Implementation Method 1
a continuous aspheric cylindrical lens disposed forward of the LED reflector between the LED reflector and the region of interest. The portion of the light output reflected toward the region of interest is reflected onto the continuous aspheric cylindrical lens which then provides redistributed light to the region of interest
Implementation Method 2
an LED reflector mounted to the LED assembly and configured to receive at least a portion of the light output and to reflect at least the portion of the light output toward a region of interest
Implementation Method 3
Some direct part marking scanners use a dome or cone-shaped diffuser to provide the totally diffuse bright field illumination for specular surfaces
Data Source
Figure 1
Figure 2A~2C
Figure 3~4
AI summary
An illumination assembly is provided for a direct part marking (DPM) scanner. The illumination assembly includes an LED assembly for generating a light output, an LED reflector mounted to the LED assembly and configured to receive at least a portion of the light output and to reflect at least the portion of the light output toward a region of interest, and a continuous aspheric cylindrical lens disposed forward of the LED reflector between the LED reflector and the region of interest. The portion of the light output reflected toward the region of interest is reflected onto the continuous aspheric cylindrical lens which then provides redistributed light to the region of interest. A dome diffuser assembly and direct part marking scanner are also provided.