Dynamic Illumination System for Bar Code Readers
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Solution Overview
Problem
Imaging-based bar code readers have limited working range due to decreasing illumination intensity with distance, leading to increased power requirements and inefficient use of energy, as they often require high-intensity illumination for longer ranges, wasting power by illuminating the entire field of view unnecessarily.
Innovation Solution
An illumination system that dynamically adjusts by activating a higher-intensity second illumination pattern when the distance to the target object exceeds a threshold, using a converging lens or reflective concentrator to focus light more intensely on the target, and can be powered by the same or separate LEDs, minimizing power usage and light pollution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a high intensity illumination system is used to extend the working range, then the imaging range is improved, but the power consumption increases and power is wasted by illuminating the entire field of view unnecessarily
Solution Approach 1:
The patent applies local quality by using a converging lens or reflective concentrator to focus the illumination light into a concentrated beam that targets only the specific region containing the bar code, rather than illuminating the entire field of view. This localized illumination approach maintains sufficient light intensity at extended distances while significantly reducing overall power consumption by directing energy only where needed.
Solution Approach 2:
The illumination system dynamically adjusts its characteristics by switching between a wide-field illumination mode for close-range scanning and a concentrated beam mode for extended-range scanning. The system adapts the illumination pattern based on the required working distance, optimizing the balance between range and power consumption for different operational conditions.
2Length of stationary object
If the distance to the target object increases, then the working range is extended, but the illumination intensity decreases
Solution Approach 1:
The patent introduces an optical intermediary element (converging lens or reflective concentrator) between the light source and the target object. This intermediary focuses and concentrates the illumination light into a directed beam, compensating for the natural decrease in intensity with distance. The concentrator acts as a mediator that maintains sufficient illumination intensity at extended distances without requiring proportionally higher power input.
3Device complexity
If a single illumination system is used for both short and long working range, then the device complexity is reduced, but the efficiency decreases due to unnecessary illumination of the entire field of view
Solution Approach 1:
The patent implements multi-functionality by enabling a single illumination system to operate in two distinct modes: wide-field illumination for close-range scanning and concentrated beam illumination for extended-range scanning. By incorporating an optical concentrator that can be activated based on the required working distance, the system achieves versatility without requiring completely separate illumination subsystems, thus balancing complexity reduction with energy efficiency.
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
Extends the operational range of the bar code reader while conserving power by only activating the second illumination pattern when necessary, reducing energy consumption and minimizing light pollution, especially at closer ranges.
Implementation Method 1
using a converging lens or reflective concentrator to focus light more intensely on the target
Implementation Method 2
using a converging lens or reflective concentrator to focus light more intensely on the target
Implementation Method 3
employ an illumination system to flood a target object with illumination from a light source such as a light emitting diodes (LED) in the reader
Data Source
AI summary
A method and apparatus for reading a target object having areas of differing light reflectivity on the target such as a handheld bar code reader having a first illumination pattern, a detector for measuring a distance from the reader to a target object, a system threshold, and a comparator for evaluating the measured distance against the threshold. Should the reader's internal circuitry and/or software determine that the measured distance is greater than the threshold, a second illumination pattern is activated that has power effective illumination for increasing the operable reading distance between the reader and the target object. The second illumination pattern can be generated from a secondary illumination source or through a lens internal to the reader.