Barcode Reader On-Axis Off-Axis Lighting Modules
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Solution Overview
Problem
Existing barcode readers face challenges in decoding two-dimensional direct part marking (DPM) barcodes, especially when the markings are on curved surfaces or in recessed areas, due to limited lighting options and angles, which affects image contrast and decoding accuracy.
Innovation Solution
A pistol grip barcode reader system with both on-axis and off-axis lighting modules, utilizing LEDs of different colors, is designed to provide simultaneous or sequential illumination at adjustable angles, enhancing image contrast and decoding capabilities by capturing bright field and dark field images simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only on-axis lighting is used, then the device structure is simple, but the decoding accuracy is insufficient for barcodes on curved or recessed surfaces
Solution Approach 1:
The lighting module is segmented into multiple independent LED light sources positioned at different angles (on-axis and off-axis), allowing each segment to illuminate the barcode from its specific direction to capture various surface features
Solution Approach 2:
The patent transitions from single-axis (on-axis only) lighting to multi-dimensional lighting by adding off-axis LEDs at various angles, enabling illumination of barcodes on curved and recessed surfaces from multiple spatial dimensions
2Adaptability or versatility
If multiple lighting angles are used to improve decoding accuracy, then the lighting coverage is enhanced, but the device complexity increases
Solution Approach 1:
Multiple LED light sources with different emission angles are merged into a single integrated lighting module assembly, providing versatile multi-angle illumination while maintaining a unified compact structure that reduces overall device complexity
Solution Approach 2:
The lighting module is designed with universal multi-functionality, where the same module with multiple LEDs can adapt to various barcode orientations and surface types (flat, curved, recessed) without requiring separate lighting systems for each case
3Measurement precision
If sequential imaging with different lighting subsets is performed, then the image contrast is improved, but the imaging time increases
Solution Approach 1:
The patent employs periodic action by sequentially activating different LED subsets (on-axis then off-axis) to capture multiple images with varying lighting conditions, improving image contrast through timed sequential imaging while maintaining efficient operation
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
The system significantly improves the decoding accuracy of DPM barcodes by generating multiple images with varying lighting angles, increasing the chances of successful decoding and adapting to different barcode orientations and surfaces.
Implementation Method 1
an on-axis lighting module that comprises first set of light emitting diodes (LEDs) having a first emitted color, said on-axis lighting module adapted to direct light on an on-axis lighting direction... said off-axis lighting module comprising a second set of LEDs having a second emitted color
Data Source
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AI summary
A system comprising: a pistol grip barcode reader (1100) adapted to obtain an image of a two dimensional direct part marking barcode, said barcode reader comprising a camera (1400), said camera defining a camera axis, said barcode reader comprising an on-axis lighting module (1500) that comprises first set of light emitting diodes (LEDs) having a first emitted color, said on-axis lighting module adapted to direct light on an on-axis lighting direction that is approximately collinear with said camera axis, said barcode reader comprising an adjustable off-axis lighting module (1700) that is substantially mirror-less, filter-less, and lens-less, said off-axis lighting module comprising a second set of LEDs having a second emitted color, said off-axis lighting module adapted to direct light in an off-axis lighting direction that intersects said camera axis at an adjustable angle, said adjustable angle less than approximately fifty five degrees, said barcode reader adapted to obtain a decodable image at a distance between approximately one inch and approximately four inches from said two dimensional direct part marking barcode.