Aim Light Assemblies for Barcode Readers Parallax Elimination
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Solution Overview
Problem
Existing barcode readers face challenges in accurately representing the field of view across their working range due to the positioning of aiming assemblies and parallax effects, leading to inaccurate indication of field of view boundaries.
Innovation Solution
The design incorporates a housing with an imaging assembly and an aiming assembly, where the aiming light is directed parallel to the boundary field of view axis using a light guide with specific surface configurations, ensuring accurate projection of aiming light patterns without parallax, even as the target moves within the working range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the aiming assembly is positioned away from the imaging elements, then the aiming assembly can be independently positioned, but the accuracy of representing field of view boundaries deteriorates due to parallax effects
Solution Approach 1:
The patent introduces a light guide as an intermediary component between the aiming light source and the target. This light guide redirects the aiming light to travel parallel to the boundary field of view axis, effectively mediating the optical path to eliminate parallax effects while allowing the aiming assembly to remain independently positioned away from the imaging elements.
2Measurement precision
If the aiming light is directed parallel to the boundary field of view axis, then the accuracy of indicating field of view boundaries improves, but the device complexity increases due to the need for light guides with specific surface configurations
Solution Approach 1:
The patent utilizes the third dimension (depth/optical path length) within the housing to accommodate the light guide's complex surface configurations. By extending the optical path through the light guide with its specifically configured surfaces, the system achieves parallel aiming light projection without increasing the external footprint of the device.
3Reliability
If the optical element redirects aiming light parallel to the boundary FOV axis, then the parallax effect is eliminated, but the manufacturing precision requirements increase for the light guide surfaces
Solution Approach 1:
The patent optimizes the light guide's surface parameters (curvature, angles, positions) to achieve the desired parallel light projection. By carefully selecting and adjusting these geometric parameters, the system achieves reliable aiming accuracy across the working range while keeping manufacturing precision requirements at achievable levels.
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
This solution enables precise indication of field of view boundaries, improving the accuracy of barcode reading across various distances without the distortion caused by parallax, allowing for easier design and operation of barcode readers.
Implementation Method 1
The optical element is configured to direct the aiming light parallel to the boundary FOV axis
Implementation Method 2
the first surface is configured to reflect the aiming light to the second surface, and the second surface is configured to reflect the aiming light to the exit surface
Implementation Method 3
The light guide is configured to receive aiming light from the aiming assembly at the entry surface and direct the aiming light parallel to the boundary FOV axis at the exit surface
Data Source
AI summary
A method and apparatus for manipulating an aiming light of a reader to indicate the field-of-view (FOV) of an imager within the reader includes an optical element. The optical element receives the aiming light from an aiming assembly and redirect the aiming light such that the central axis of the aiming light exiting the optical element is non-coaxial with the central aiming axis of the aiming assembly at the entry of the optical element. The optical element may be configured to project an image on a target that indicates the boundary of the FOV or project an image on the target that indicates the center of the FOV.