Laser Scan Line Intensity Control via Source Blanking
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Solution Overview
Problem
Existing laser scanning code symbol reading systems lack flexibility in controlling the length and intensity characteristics of the laser scan line, particularly at extreme positions where the beam decelerates and accelerates, leading to undesirable energy characteristics and safety issues.
Innovation Solution
Implementing a system that automatically deactivates the laser beam source at the extreme end positions of the scan line using programmed firmware responsive to start and end of scan signals, controlling the visible laser diode source to prevent intensity variations and eliminate bright spots, and employing dual-laser scanning with different scanning rates for long and short range scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the laser scan angle is fixed to maintain a sufficient scan line length, then the scan line covers the required area, but the laser beam intensity varies at extreme positions causing safety issues and aesthetic problems
Solution Approach 1:
The system performs preliminary action by deactivating the laser source before the beam reaches extreme positions where intensity variations occur. The firmware monitors beam position and preemptively turns off the laser source when approaching scan line endpoints, preventing the formation of bright spots and intensity variations before they occur.
Solution Approach 2:
The system applies preliminary anti-action by implementing a control mechanism that counteracts the natural tendency of the laser beam to create intensity variations at extreme positions. The firmware detects approaching extreme positions and activates the laser source deactivation in advance, creating a protective effect against harmful intensity variations.
2Duration of action of moving object
If the laser source remains active throughout the scanning cycle, then continuous scanning coverage is achieved, but undesirable bright spots and intensity variations occur at extreme positions
Solution Approach 1:
The firmware performs preliminary action by deactivating the laser source in advance before the beam reaches extreme positions. This timing-based control ensures that the laser is turned off just before intensity variations would occur, maintaining continuous scanning coverage while preventing harmful bright spots.
Solution Approach 2:
The system implements periodic action by cyclically activating and deactivating the laser source during the scanning cycle. The laser remains active during the central portion of the scan and is periodically deactivated at extreme positions, creating a rhythmic on-off pattern that eliminates intensity variations while maintaining overall continuous scanning.
3Object-affected harmful factors
If the laser beam is deactivated at extreme end positions to eliminate intensity variations, then safety and aesthetic quality improve, but the scan line length is reduced
Solution Approach 1:
The system applies local quality by selectively deactivating the laser source only at extreme end positions where intensity variations occur, while maintaining laser activity in the central scanning region. This localized control preserves the majority of the scan line length while eliminating harmful effects only where necessary.
Solution Approach 2:
The firmware implements partial action by deactivating the laser source for only a portion of the scanning cycle - specifically at extreme positions - rather than throughout the entire cycle. This partial deactivation is sufficient to eliminate intensity variations while minimizing impact on overall scan line length.
4Device complexity
If a single laser source is used for scanning, then the system structure is simple, but flexibility in controlling scan line characteristics is limited
Solution Approach 1:
The system implements dynamics by making the laser source activation state variable rather than fixed. The firmware dynamically adjusts the laser source state based on real-time beam position feedback, transitioning between active and inactive states to provide flexible control over scan line characteristics while maintaining a simple single-source structure.
Solution Approach 2:
The system applies parameter changes by varying the temporal activation parameters of the laser source during the scanning cycle. The firmware modifies the laser duty cycle and timing characteristics dynamically, changing when the laser is active versus inactive to achieve flexible control over scan line length and intensity without adding physical complexity.
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 provides improved control over the length and intensity of the laser scan line, enhancing safety and aesthetic quality by eliminating intensity variations and bright spots, while allowing for flexible scanning of objects with specific length projections.
Implementation Method 1
a visible laser beam generated by a laser source
Implementation Method 2
laser scanning beam repeatedly scans across a code symbol
Data Source
AI summary
Method of and system for reading bar code symbols using a hand-supportable laser scanning bar code symbol reading system supporting an improved level control over the length and intensity characteristics of laser scan lines projected onto scanned objects, at any instant in time, in a manner dependent the detected location, distance or range of the scanned object in the scanning field of the system during system operation. The system includes a laser scanning module that projects the laser scanning beam through a light transmission window, and across a laser scanning field in which an object is located, while the laser scanning beam is blanked out during the laser scanning cycle according to a laser source blanking function that is determined by the estimated distance, or data representative thereof.