Laser Power Regulation Circuit for Electro-Optical Readers
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Solution Overview
Problem
Existing electro-optical readers face challenges in enhancing processing speed and accuracy due to significant software processing burdens from laser power control, with current systems being sluggish and having reduced measurement accuracy, especially when using lasers with higher slope efficiencies.
Innovation Solution
A hardware-based circuit arrangement that includes a feedback circuit, disabling circuit, drive circuit, current modification circuit, and control circuit to regulate laser output power, allowing for periodic and momentary disabling of the feedback circuit to ease software processing burdens and increase measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If software-based laser power control is used, then laser output can be regulated, but processing speed decreases and measurement accuracy reduces
Solution Approach 1:
The patent replaces the software-based control system with a hardware-based circuit system. The control circuit with comparator, timer, and power switch directly monitors laser current and output power through the monitor photodiode, eliminating the need for software processing. This hardware implementation provides faster response times and higher measurement accuracy simultaneously.
Solution Approach 2:
The monitor photodiode internally mounted in the laser assembly provides self-monitoring capability. The circuit uses the laser's own output light to generate a monitor signal that directly reflects the actual output power, creating a self-regulating system that improves both accuracy and speed without external intervention.
2Stability of the object's composition
If feedback circuit is continuously active, then laser power is stabilized, but software processing burden increases
Solution Approach 1:
The continuous software feedback loop is replaced with a hardware feedback circuit. The control circuit continuously monitors the monitor photodiode output and automatically adjusts the power switch based on real-time conditions, providing continuous stabilization without software intervention and eliminating the associated processing burden.
Solution Approach 2:
The patent implements a hardware feedback mechanism where the control circuit continuously compares the actual laser output power (via monitor photodiode) with the desired power level and automatically adjusts the power delivery through the power switch. This closed-loop hardware feedback provides continuous stabilization while avoiding software processing complexities.
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 enhances processing speed and accuracy by reducing the software burden on the controller and increasing the magnitude of information signals, enabling the use of lasers with higher slope efficiencies while maintaining safe power levels within regulatory limits.
Implementation Method 1
an internal semiconductor monitor photodiode, for monitoring the output power of the laser beam
Implementation Method 2
a feedback circuit connected between the monitor photodiode and the laser chip, for maintaining substantially constant the output power of the laser beam during normal operation
Data Source
AI summary
In an electro-optical reader, an aiming or a scanning laser has a laser chip and a monitor photodiode. Output power of a laser beam emitted by the laser is regulated by a feedback circuit for maintaining substantially constant the laser beam output power during normal operation, a disabling circuit for disabling the feedback circuit, a drive circuit for driving the chip with a drive current when the feedback circuit is disabled, and for concomitantly generating a photodiode output voltage, a current modification circuit for modifying the drive current by a predetermined current with a concomitant change in the photodiode output voltage when the feedback circuit is disabled, and a control circuit for monitoring the change in the photodiode output voltage, for determining whether the change in the photodiode output voltage is sufficient to indicate an over-power condition, and for interrupting power to the chip when the over-power condition is indicated.