Slim Mobile Barcode Scanner Illumination Module for DPM Scanning
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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 like dome shape or ring shape illuminators.
Innovation Solution
Integration of a symmetric, multi-color illumination module with dark field and bright field capabilities, including tri-color LEDs, close-up corrective lenses, and near-coaxial aimer optics, to prevent specular reflection and enhance scanning performance in slim mobile data terminals and smart mobile phones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a typical scanner illuminator with close proximity to the imaging lens is used, then the device size is reduced, but strong specular reflection contaminates the image especially for highly reflective barcode
Solution Approach 1:
The illumination system is segmented into multiple independent LED light sources positioned at different locations and angles around the imaging lens. Each LED provides illumination from a specific direction, allowing the system to avoid specular reflection while maintaining compact size. The segmentation of illumination sources enables selective positioning to achieve optimal scanning angles for DPM barcodes.
Solution Approach 2:
Different regions of the illumination module provide different illumination characteristics. LEDs are strategically positioned to create localized illumination zones with specific incident angles. The illuminator includes LEDs at high incident angles for dark field illumination and LEDs at lower incident angles for bright field illumination, allowing local optimization of illumination quality for different barcode types.
2Object-affected harmful factors
If dedicated DPM imaging scanner approaches such as dome shape illuminator or ring shape dark field illuminator are used, then specular reflection is prevented, but the space requirement cannot be met in slim mobile devices
Solution Approach 1:
The illumination system transitions from traditional two-dimensional planar illuminators to a three-dimensional arrangement of multiple LED sources positioned at various heights and angles around the imaging lens. This spatial distribution in multiple dimensions allows the system to achieve dark field and bright field illumination effects without requiring the large volume of dome or ring illuminators, fitting within the constrained space of slim mobile devices.
Solution Approach 2:
The system changes the illumination parameters by using multiple LEDs with different incident angles, colors, and intensities. By adjusting the illumination angle parameter to high angles for dark field mode and lower angles for bright field mode, the system achieves effective DPM scanning without increasing physical volume. The multi-color LED capability allows parameter changes in wavelength to optimize contrast for different barcode materials.
3Adaptability or versatility
If multi-color LEDs with different incident angles are used, then DPM barcode scanning capability is improved, but the device complexity increases
Solution Approach 1:
The illumination module uses multi-color LEDs that can emit different wavelengths (red, green, blue) to provide universal illumination capability for various barcode types including paper, metallic, and laminated materials. The same physical LED component serves multiple functions by changing color, reducing the need for separate illumination systems for different barcode types and simplifying the overall device structure despite the enhanced capability.
Solution Approach 2:
Multiple illumination functions (dark field, bright field, different colors) are merged into a single integrated illumination module. Instead of having separate illuminators for each function, the patent combines multiple LEDs with different characteristics into one compact module that can switch between different illumination modes electronically, reducing structural complexity while maintaining versatility.
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 and aiming support, improving scanning accuracy and contrast in size-restricted mobile devices.
Implementation Method 1
a first and second diffuser that diffuse light emitted by the first and second bright field multi-color LED, respectively
Implementation Method 2
a close-up corrective lens that provides imaging for close-up reading
Implementation Method 3
The first and second dark field multi-color LED provide high incident angle light for the dark field illumination to prevent specular reflection entering an imaging lens field of view
Data Source
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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.