Multi-Color Illumination Module for Slim Barcode Scanner
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Solution Overview
Problem
Mobile imaging barcode scanners face difficulties in reading direct product marking (DPM) barcodes due to strong specular reflection, especially with metallic or laminated materials, and lack the space for dedicated DPM imaging scanner approaches.
Innovation Solution
Integration of a symmetric, multi-field, multi-color illumination module with dark field and bright field capabilities, including tri-color LEDs, diffusers, and near-coaxial aimer optics, within a slim mobile data terminal or smart mobile phone to prevent specular reflection and enhance barcode scanning performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a typical scanner illuminator is placed close to the imaging lens, then the device size is reduced, but strong specular reflection contaminates the image especially for highly reflective barcodes
Solution Approach 1:
The illumination system is segmented into multiple LED sources positioned at different locations around the imaging lens, with each LED providing illumination from a specific angle. This segmentation allows the system to maintain compact dimensions while controlling specular reflection through strategic placement of multiple smaller illumination sources rather than a single large illuminator
Solution Approach 2:
Different regions of the illumination system provide different illumination characteristics - LEDs positioned at higher angles provide dark field illumination for reflective surfaces, while centrally positioned LEDs provide bright field illumination for non-reflective surfaces. This local differentiation of illumination quality allows the compact scanner to handle various barcode types effectively
2Reliability
If dedicated DPM imaging scanner approaches (dome shape illuminator or ring shape dark field illuminator) are used, then reading capability for metallic or laminated barcodes is improved, but the space requirement cannot be met in slim mobile devices
Solution Approach 1:
The patent merges multiple illumination functions (dark field and bright field) into a single integrated LED module that surrounds the imaging lens. By combining multiple LED sources, diffusers, and reflectors into one compact assembly, the system achieves DPM reading capability without requiring separate dome or ring illuminator structures
Solution Approach 2:
The illumination system transitions from traditional two-dimensional plane illuminators to a three-dimensional arrangement of LEDs positioned at various heights and angles around the lens. This spatial distribution in multiple dimensions allows the compact module to provide both dark field and bright field illumination simultaneously without increasing overall footprint
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
Enables effective reading of DPM barcodes by minimizing specular reflection and providing optimal illumination for both dark and bright field conditions, improving scanning accuracy and contrast within the limited space of mobile devices.
Implementation Method 1
The illumination module can comprise a first and a second dark field multi-color LED (e.g., a tri-color LED) and a first and second bright field multi-color LED (e.g., a tri-color LED)
Implementation Method 2
a first and second diffuser. The first dark field multi-color LED and the first end dark field light block are proximate to one end of the illumination module
Implementation Method 3
a close-up corrective lens; The close-up corrective lens can provide imaging for near range reading
Implementation Method 4
The first and a second dark field multi-color LED (e.g., a tri-color LED) and the first and the second dark field multi-color LED (e.g., a tri-color LED) can provide a high incident angle light for the dark field illumination to prevent specular reflection entering an imaging lens field of view
Data Source
AI summary
Performance and size improvements in indicia readers are disclosed. The improvements provide for the integration of a barcode image scanner in a size restricted mobile computer device, such as a slim mobile data terminal or a smart mobile phone, and provide for the ability for the indicia reader to read direct product marking (DPM) type of barcodes. The improvements include the incorporation of an illumination module or bar that can generate dark field and bright field illumination. The illumination module can be designed to match the front end of a smart mobile phone and maintain a low profile design. Symmetric arranged multi-field, multi-color illuminator with close-up corrective lens and near coaxial aimer optics provide illumination and aiming support for the DPM scanning. The improvements allow the indicia reader, assembled in a slim mobile data terminal, to read direct product marking (DPM) type of barcodes.