Scheimpflug Code Reader Illumination for Uniform Far-Field Brightness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Code readers using a Scheimpflug optical system face issues with non-uniform brightness between near and far fields, leading to insufficient illuminance on the far side, which affects the readability of codes.
Innovation Solution
The code reader employs multiple illumination units with different light distribution angles and optical axis intersections to form a focal plane, ensuring uniform brightness across the near and far sides by adjusting the overlap and distribution of narrow-angle and wide-angle illumination light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a Scheimpflug optical system is used to deepen the depth of field, then the ability to read codes at various distances is improved, but the uniformity of brightness between near and far fields deteriorates
Solution Approach 1:
The patent applies local quality by using multiple illumination units with different light distribution angles (narrow-angle and wide-angle) to provide differentiated illumination to different regions (near field and far field). Each illumination unit is optimized for its specific target region, allowing the near side and far side to receive appropriate illumination levels tailored to their respective distances from the imaging unit.
Solution Approach 2:
The illumination system is segmented into multiple independent illumination units, each with specific light distribution characteristics. The narrow-angle illumination units are positioned to illuminate the near field, while wide-angle illumination units cover the far field. This segmentation allows independent optimization of illumination for each region without compromising the other.
2Illumination intensity
If multiple illumination units with different light distribution angles are used, then brightness uniformity is improved, but device complexity increases
Solution Approach 1:
Each illumination unit in the patent is designed to serve multiple purposes: they provide illumination for code reading while also contributing to the overall lighting distribution pattern. The narrow-angle and wide-angle illumination units work together to create a comprehensive illumination system that handles both near and far field requirements, making each component multi-functional in the context of achieving uniform brightness.
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 enhances code readability by maintaining consistent illuminance, allowing for efficient decoding of codes both near and far from the imaging unit, regardless of their distance.
Implementation Method 1
a lens collecting reflected light from the code attached to the workpiece
Implementation Method 2
a Scheimpflug optical system including a lens collecting reflected light from the code attached to the workpiece and an image sensor having a light receiving surface inclined with respect to an optical axis of the lens
Implementation Method 3
a plurality of illumination units that irradiate the workpiece with illumination light
Data Source
AI summary
A code reader includes: a plurality of illumination units that irradiate the workpiece with illumination light; an imaging unit that includes a Scheimpflug optical system and generates and outputs a code image; and a control unit that executes decoding processing on the code image. The Scheimpflug optical system is used to form a focal plane extending from a near side to a far side of the imaging unit and make light distribution angles of the plurality of illumination units different or make positions where optical axes of the plurality of illumination units intersect the focal plane different in a direction in which the focal plane extends to suppress insufficiency of illuminance on the far side with respect to the near side of the focal plane or to make illuminance on the far side equal to or higher than illuminance on the near side.