Coaxial Aimer Imager Assembly for Barcode Scanners
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Solution Overview
Problem
Modern imaging barcode scanners face aiming errors due to the offset between the imaging lens axis and the aimer lens, which is exacerbated by the small size and close proximity of barcodes, leading to difficulties in reading small codes effectively.
Innovation Solution
A coaxial aimer imager assembly and aimer pattern projector assembly that aligns the aimer pattern coaxially with the imaging lens, using LED light sources, aperture plates, and projector lenses to create a central aimer pattern that matches the image field of view, ensuring accurate targeting and barcode reading across various distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the aimer projector is disposed off-axially relative to the imaging lens to avoid space conflict, then the device structure is simplified, but aiming error increases especially at near field viewing
Solution Approach 1:
The patent merges the aimer projector and imaging lens into a coaxial arrangement, combining their optical paths along the same axis. This eliminates the offset between aimer beam center and image line of sight, resolving the aiming accuracy issue while maintaining compact device structure through shared optical components.
Solution Approach 2:
The patent introduces a beam splitter as an intermediary component that separates the aimer projector beam from the imaging lens axis while maintaining coaxial alignment. This allows the aimer pattern to be superimposed on the image field without requiring physical separation, thus maintaining both structural simplicity and aiming precision.
2Measurement precision
If conventional optical approach with beam splitter is used to superimpose aimer projector beam onto imaging lens axis, then aiming accuracy is improved, but device dimensions increase and image quality degrades
Solution Approach 1:
The patent extracts the beam splitter from the optical path and replaces it with direct coaxial alignment of the aimer projector with the imaging lens. This eliminates the additional optical component, reducing device dimensions and avoiding image quality degradation while maintaining aiming accuracy through precise coaxial positioning.
3Measurement precision
If tilting the aiming beam is used to compensate for offset error, then aiming accuracy is improved at certain object distance, but the solution becomes ineffective at other distances especially for very close small barcodes
Solution Approach 1:
The patent creates a universal coaxial aimer system that functions effectively at all object distances, from very close small barcodes to distant targets. The coaxial alignment ensures the aimer pattern remains centered in the image field regardless of distance, eliminating the need for distance-specific adjustments and providing consistent aiming accuracy across all ranges.
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 solution provides precise alignment and improved image quality by ensuring the aimer pattern is centered with the image field of view, reducing aiming errors and enhancing the ability to read small barcodes at close distances without degrading image quality.
Implementation Method 1
an LED light source, an LED aperture plate, and a projector lens disposed in front of and coaxial with the LED aperture plate and the LED light source
Implementation Method 2
a lens array or panel positioned adjacent the circuit board assembly for focusing an even pattern of illumination on the target area
Data Source
AI summary
An aimer pattern projector assembly (200, 300) includes an LED light source (212, 312), an LED aperture plate (204, 304), and a projector lens (206, 306) disposed in front of and coaxial with the LED aperture plate (204, 304) and the LED light source (212, 312). The LED light source (212, 312), aperture plate (204, 304), and projector lens (206, 306) each have a central opening configured to accommodate and coaxially align with a line of sight of an imaging lens. The LED light source (212, 312) can include two or more LEDs operably coupled to a PCB. A coaxial aimer imager assembly (100) can include an imaging lens-sensor module (102) and the aimer pattern projector assembly. A method for scanning includes generating a combined aimer pattern coaxially aligned with a line of sight of an image of the object.