Folded Illuminating Path for Uniform Far-Distance Symbol Reading
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Solution Overview
Problem
Existing imaging readers face challenges in uniformly illuminating symbols located at far distances due to constraints in the number and location of illuminating light elements within standardized module dimensions, leading to insufficient light capture and processing for successful reading.
Innovation Solution
The imaging reader employs a folded illuminating path that is longer than the imaging path, with illumination light sources mounted further from the front than the imager, and includes reflectors and aperture stops to direct and focus light effectively, enhancing light throughput and reading performance for far-out symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the illuminating light assembly uses a conventional direct path configuration, then the module dimensions can be kept compact, but the illumination intensity and uniformity at far distances are insufficient
Solution Approach 1:
The patent introduces a folded illuminating path that extends in multiple dimensions within the module housing, using reflective surfaces to redirect light at different angles. This allows the light to travel a longer effective path length without increasing the linear dimensions of the module, thereby achieving both compact size and enhanced far-distance illumination intensity
Solution Approach 2:
The illuminating path is nested within the module housing by using reflective surfaces and angled arrangements that allow the light to fold back on itself multiple times within the available space. This nesting approach maximizes the illuminating path length within the constrained module dimensions
2Area of stationary object
If the illuminating light assembly is configured to illuminate far-out symbols, then the illumination coverage is improved, but the number and location of light elements exceed the constraints of standardized module dimensions
Solution Approach 1:
The illuminating assembly is segmented into multiple light-emitting diodes positioned at different locations within the module, each contributing to different portions of the illumination coverage. This segmentation allows the system to achieve wide-area illumination without requiring a single complex light element, thereby managing device complexity while expanding coverage area
Solution Approach 2:
The reflective surfaces and optical elements are designed to serve multiple functions: they redirect light from different LED sources, focus light onto the target, and maintain uniform illumination across the field of view. This multi-functionality reduces the total number of separate components needed while achieving comprehensive illumination coverage
3Quantity of substance
If the folded illuminating path is made longer, then the amount of illumination light directed to the target increases, but the f-number decreases requiring more precise optical control
Solution Approach 1:
Aperture stops are introduced as intermediary elements within the folded illuminating path to control and regulate the amount of light passing through each section. These aperture stops provide precise control over the effective f-number, allowing the system to maintain optimal illumination intensity while managing the complexities introduced by the extended folded path
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 ensures greater illumination and return light capture, improving imaging performance, especially for symbols located far from the reader, by increasing the amount of illumination light directed to the target and enhancing the strength of the electrical signal for successful reading.
Implementation Method 1
a solid-state imager with a sensor array of cells or photosensors, which correspond to image elements or pixels in a field of view of the imager, and imaging elements for capturing return light scattered and/or reflected from the symbol being imaged
Implementation Method 2
the imaging module generally also includes an illuminating light assembly having one light source or a plurality of light sources, e.g., light emitting diodes (LEDs)
Implementation Method 3
a plurality of illuminating elements, e.g., lenses and aperture stops, to uniformly illuminate the symbol with the illumination light for reflection and scattering therefrom
Implementation Method 4
capturing return light over a field of view at a range of working distances from the target along a folded imaging path
Data Source
AI summary
An imaging module for imaging, and a reader for and a method of electro-optically reading, a target, include a support, an imaging assembly including a solid-state imager having an array of image sensors on the support for capturing return light over a field of view at a range of working distances from the target along a folded imaging path, and an illuminating assembly on the support for directing illumination light along a folded illuminating path having a length longer than the folded imaging path to uniformly illuminate the target with the illumination light. The longer length of the folded illuminating path enables the illuminating assembly to illuminate the target with more of the illumination light, and also enables the imaging assembly to capture more of the return light for increased imaging/reading performance.