Diffuse Bright Field Illumination for Barcode Center Zone
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Solution Overview
Problem
Barcode readers face challenges in providing optimal illumination for the 'center zone' of their field of view, as existing bright field and dark field illumination systems are not sufficiently diffuse or bright enough, and often overlap with the far and close zones, respectively.
Innovation Solution
A diffuse bright field illumination system is introduced, featuring light-diffusing characteristics and illumination elements on the edges of an optic, which directs diffuse illumination parallel to the optical axis, addressing the insufficiencies of traditional systems by providing uniform illumination for the center zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a bright field illumination system is used, then illumination intensity for far zone is improved, but illumination diffuseness for center zone deteriorates
Solution Approach 1:
The patent divides the field of view into distinct zones (far zone, center zone, close zone) and assigns different illumination characteristics to each zone. The bright field illumination system provides high intensity for the far zone, while the diffuse bright field illumination system provides diffuse illumination for the center zone. This local differentiation resolves the contradiction by allowing each zone to receive optimally tailored illumination without compromising the other.
Solution Approach 2:
The illumination system is segmented into multiple independent subsystems: a bright field illumination system for the far zone and a diffuse bright field illumination system for the center zone. Each subsystem can be independently controlled and optimized for its specific zone, allowing the system to simultaneously provide both high intensity and diffuse illumination where needed without the trade-off present in a single unified system.
2Ease of operation
If a dark field illumination system is used, then illumination diffuseness for close zone is improved, but illumination intensity for center zone deteriorates
Solution Approach 1:
The patent applies local quality by providing dark field illumination with high diffuseness for the close zone while introducing a separate diffuse bright field illumination system that provides high intensity for the center zone. This allows the center zone to receive both the diffuseness needed for even coverage and the intensity needed for bright illumination, resolving the contradiction between these two properties.
Solution Approach 2:
The patent merges multiple illumination systems (dark field, bright field, and diffuse bright field) into a single integrated illumination apparatus. This combination allows the system to simultaneously provide dark field illumination for the close zone and diffuse bright field illumination for the center zone, eliminating the need to choose between diffuseness and intensity for any given zone.
3Device complexity
If a single illumination system is used, then device complexity is reduced, but illumination performance across different zones deteriorates
Solution Approach 1:
The patent creates a universal illumination system that can serve multiple zones with different illumination requirements through a single integrated apparatus. The illumination system includes multiple illumination elements and optical components that work together to provide far zone, center zone, and close zone illumination, allowing one system to perform multiple functions that would otherwise require separate systems.
Solution Approach 2:
The patent employs a nested structure where multiple illumination subsystems are integrated within a single illumination apparatus. The diffuse bright field illumination system and bright field illumination system are nested within the same housing and optical path, with each subsystem contributing to different zones. This nested arrangement maintains compactness while providing zone-specific optimization.
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 diffuse bright field illumination system enhances barcode reading accuracy and speed by ensuring consistent illumination across the center zone, improving reading capabilities beyond the limitations of traditional bright and dark field systems.
Implementation Method 1
Light that is introduced from the at least one light source is transferred by total internal reflection between a front major surface and a back major surface in a direction transverse to an optical axis of a camera
Implementation Method 2
one or more extraction features configured to extract light from the optical substrate and into the field of view
Data Source
AI summary
One aspect of the present disclosure is related to a barcode reader that includes a bright field illumination system, a dark field illumination system, and an additional illumination system that is better able to illuminate an area of the reader's field of view between the far zone (where bright field illumination is optimal) and the close zone (where dark field illumination is optimal). In this “center zone,” the dark field illumination may not be bright enough and the bright field illumination may not be diffuse enough for reading a barcode.