Flicker-Corrected Aimer and Alternating Illumination for Screen Reading
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Solution Overview
Problem
Existing indicia reading terminals experience significant flickering effects in both illumination and aimer subsystems during screen reading modes, leading to distracting and uncomfortable operations when reading bar codes from mobile phones or other LED screens.
Innovation Solution
The implementation of an indicia reading terminal with a flicker-corrected screen reading mode, which activates the imaging subsystem during both illuminated and unilluminated exposure periods, with equal intervals between active aimer periods, to reduce or eliminate flickering effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the imaging subsystem is activated during both illuminated and unilluminated exposure periods with the aimer subsystem activated only during unilluminated periods, then flickering effects are reduced or eliminated, but the complexity of timing coordination between subsystems increases
Solution Approach 1:
The patent implements periodic action by establishing regular, alternating exposure cycles where the imaging subsystem is activated during both illuminated and unilluminated periods at equal intervals. The aimer subsystem is activated only during unilluminated periods in a periodic manner, creating a rhythmic pattern that eliminates flickering effects while maintaining systematic coordination through predetermined timing sequences.
2Measurement precision
If unilluminated exposure periods are made significantly longer to avoid specular reflection, then reading accuracy improves, but the overall reading speed decreases
Solution Approach 1:
The patent resolves this contradiction by implementing periodic action with equal intervals between illuminated and unilluminated exposure periods. This creates a balanced rhythm where the imaging subsystem alternates between illuminated and unilluminated exposures at regular intervals, ensuring that unilluminated periods are sufficiently long to avoid specular reflection and maintain reading accuracy, while the overall cycle frequency is optimized to preserve reading speed.
3Reliability
If the aimer subsystem is activated continuously, then target acquisition is improved, but flickering effects become more noticeable and distracting
Solution Approach 1:
The patent applies periodic action by activating the aimer subsystem only during unilluminated periods in a regular, periodic manner. This timing strategy ensures that the aimer is active during periods when illumination is off, thereby maintaining target acquisition reliability while eliminating the flickering effects that would occur if the aimer were activated during illuminated periods or continuously.
4Object-affected harmful factors
If illuminated exposure periods are shortened to reduce flickering, then flicker correction improves, but the quality of illuminated readings deteriorates
Solution Approach 1:
The patent resolves this contradiction through periodic action by establishing equal intervals between illuminated and unilluminated exposure periods. This periodic structure ensures that illuminated exposure periods are maintained at optimal durations for reading quality, while the regular alternation with unilluminated periods provides sufficient darkness for flicker correction, achieving both goals through balanced rhythmic cycling.
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 approach significantly reduces or eliminates noticeable flickering, enhancing the comfort and efficiency of reading indicia on device screens by optimizing exposure periods and maintaining regular periodicity in illumination and aimer activations.
Implementation Method 1
an illumination subsystem operative for projecting of an illumination pattern
Implementation Method 2
an aimer subsystem operative for projecting an aiming pattern
Implementation Method 3
an imaging optics assembly operative for focusing an image onto the image sensor array
Implementation Method 4
an image sensor array and an imaging optics assembly operative for focusing an image onto the image sensor array
Data Source
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AI summary
An indicia reading terminal is disclosed that eliminates unwanted flickering effects in an illuminated screen reading mode, among other advantageous features. The indicia reading terminal, in response to a screen reading signal, is operative to activate a screen reading cycle. In the screen reading cycle, an imaging subsystem is activated at least once at the same time that an illumination subsystem is activated for one of a plurality of active illumination periods, for a first illuminated exposure period. The imaging subsystem is activated at least once while the illumination subsystem is not activated, for a first unilluminated exposure period, which is longer than the first illuminated exposure period. An aimer subsystem is activated for a plurality of active aimer periods when neither the imaging subsystem or the illumination subsystem is activated, wherein intervals of time between the active aimer periods are equal, within nominal tolerances.