Imaging Reader Thermal Management via Conductive Chassis
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Solution Overview
Problem
Imaging readers face performance degradation and reduced operational lifetimes due to excessive heat generation from high-powered illumination sources, especially in hot environments or poorly ventilated housings, which can damage LEDs and other components.
Innovation Solution
Implementing thermal management procedures such as surface-mounting LEDs on both sides of a printed circuit board with thermally conductive lands, using a thermally conductive chassis as a heat sink, and employing thermal sensors to monitor temperature and adjust operations to reduce heat, including reducing drive current, turning off components when overheating is detected, and altering imaging frame rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high-powered illumination LEDs are driven at high electrical currents to improve reading performance, then illumination intensity is improved, but excessive heat is generated causing component degradation and reduced operational lifetime
Solution Approach 1:
A thermally conductive chassis is introduced as an intermediary heat sink between the illumination LEDs and the surrounding environment. The chassis provides a dedicated thermal conduction path that mediates heat transfer away from the LEDs, allowing high illumination currents to be used without excessive temperature rise in the critical components.
Solution Approach 2:
The chassis is designed to serve multiple functions: it provides mechanical support for the imager and illumination sources, while simultaneously acting as a thermally conductive heat sink. This multi-functionality allows the same structure to address both mechanical mounting and thermal management needs.
2Productivity
If high electrical drive currents are used to illuminate the symbol for better reading performance, then reading performance is improved, but operational lifetime of components is reduced due to heat generation
Solution Approach 1:
The thermally conductive chassis acts as a heat sink intermediary that protects time-sensitive components (LEDs, imager) from thermal damage. By providing this thermal buffer, the system can sustain high illumination currents for improved reading performance without compromising component operational lifetime.
Solution Approach 2:
A thermal sensor provides real-time temperature feedback about the chassis or nearby components. This feedback enables the controller to adjust operational parameters dynamically, maintaining reading performance while preventing conditions that would reduce operational lifetime through excessive heat.
3Volume of moving object
If the reader operates in a hot environment or housing with poor ventilation, then portability and compactness are improved, but heat dissipation becomes insufficient causing overheating
Solution Approach 1:
The thermally conductive chassis serves as an internal heat management intermediary that compensates for poor external ventilation. By providing efficient internal thermal conduction paths, the chassis enables effective heat dissipation even when the housing itself is compact or poorly ventilated, allowing portable designs without sacrificing thermal management.
4Reliability
If thermal management procedures are implemented to dissipate heat, then operational lifetime is improved, but device complexity increases
Solution Approach 1:
The chassis is designed to perform multiple functions simultaneously: mechanical support for components and thermal conduction for heat dissipation. This multi-functionality allows thermal management to be achieved without adding separate dedicated cooling structures, thereby minimizing the increase in device complexity while still improving operational lifetime.
Solution Approach 2:
The thermally conductive chassis provides passive thermal management through its inherent thermal conduction properties. The heat sink function operates automatically based on temperature gradients without requiring active control mechanisms, reducing the complexity of thermal management while still protecting components.
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 lifetimes of LEDs, imagers, and other components, enhancing reader performance by effectively dissipating excess heat and preventing overheating.
Implementation Method 1
A hole extends through the opposite surfaces of the board and is internally plated and lined with a thermally conductive, metallized layer... to conduct the excess heat away from the LED
Implementation Method 2
using a thermally conductive chassis as a heat sink
Implementation Method 3
The illumination light source is preferably at least one light emitting diode (LED)
Implementation Method 4
A one- or two-dimensional, solid-state imager is mounted in the imaging reader, and includes an array of image sensors operative for capturing return light from a one- or two-dimensional symbol
Data Source
AI summary
A reader for electro-optically reading indicia, includes a solid-state imager including an array of image sensors for capturing return light from the indicia during reading, and a light source for generating and directing high intensity illumination light to the indicia with concomitant generation of excess heat. Thermal management procedures for dissipating the excess heat are performed to improve reader performance.