Barcode Reader LED Illumination Control for Power and Noise Reduction
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Solution Overview
Problem
Conventional barcode readers consume excessive power due to constant LED illumination, regardless of reading distance, leading to rapid battery drain and potential noise in output data from surge voltage changes during lighting adjustments.
Innovation Solution
An optical information reader with an image sensor and an illuminator, featuring a lighting time adjuster and controllers to synchronize LED lighting with image sensor operations, ensuring light is only on during necessary exposure times and avoiding surge voltage effects, with mode switching based on lighting and output times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the LED is continuously lighted for one frame time to ensure sufficient illumination for long distance reading, then the illumination intensity is maintained, but the power consumption increases and battery life decreases
Solution Approach 1:
The patent applies dynamics by making the LED lighting duration adaptive rather than fixed. The lighting time is dynamically adjusted based on the detected reading distance, allowing the system to use longer illumination for distant barcodes and shorter illumination for nearby barcodes, thus optimizing the balance between illumination quality and power consumption
Solution Approach 2:
The patent changes the parameter of lighting duration based on reading distance conditions. By detecting the distance to the barcode and adjusting the LED on-time accordingly, the system modifies the illumination parameter to match the actual reading requirements, reducing unnecessary power consumption while maintaining sufficient illumination when needed
2Use of energy by moving object
If the LED lighting time is adjusted to reduce power consumption, then battery life is extended, but surge voltage may occur during light-ON and light-OFF switching causing noise in output data
Solution Approach 1:
The patent applies preliminary action by stabilizing the LED current before switching occurs. The control circuit waits for the current to reach a stable state after turning the LED on or off before proceeding with data output or frame timing, preventing surge voltage from affecting the sensor readings and ensuring data integrity
Solution Approach 2:
The patent introduces an intermediary control mechanism between the LED switching and data output processes. The control circuit acts as a mediator that coordinates the timing between LED illumination changes and sensor data acquisition, ensuring that surge voltage does not interfere with the output data while still enabling dynamic lighting adjustment
3Productivity
If the frame time is extended to accommodate longer data output time, then complete data can be output, but the overall reading speed decreases
Solution Approach 1:
The patent segments the frame time into distinct functional periods: LED illumination time, data output time, and processing time. By separating these functions temporally, the system can optimize each independently - using sufficient illumination time for accurate reading while keeping the overall frame time manageable to maintain reading speed
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
Reduces power consumption and prevents data noise by optimizing LED lighting duration according to reading distance, maintaining data integrity and extending battery life.
Implementation Method 1
a CPU 10 generates an LED (Light Emitting Diode) control signal and controls light emission intensity of an LED 20 to illuminate a barcode
Implementation Method 2
A barcode image formed with an image pickup lens on a light receiving surface of the sensor is converted into an electric signal with the linear image sensor 30
Data Source
AI summary
In a barcode reader, a sensor controller sets time of one frame of a line image sensor based on output time necessary for data output of one frame from the line image sensor and lighting time of an LED. A light source controller performs first lighting control to turn on the LED only for the lighting time after termination of the data output within the time of one frame, and second lighting control to turn on the LED only for the lighting time so as to include the entire period of the data output within the time of one frame.