Refrigerated Drying Module for Moisture-Sensitive Device Storage
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Solution Overview
Problem
Moisture-sensitive electronic components, commonly used in surface mount technology, are prone to internal defects due to moisture absorption during the assembly process, which are difficult to detect and can lead to early system failure. Conventional low humidity storage methods are either costly, time-consuming, or ineffective in removing absorbed moisture, posing risks of component oxidation or prolonged storage downtime.
Innovation Solution
A refrigerated drying module with a storage cabinet and a refrigerant loop that circulates air through an evaporator coil, freezing moisture as ice to maintain a low humidity environment, thereby preventing moisture absorption and reducing the risk of component damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dry storage boxes with desiccants are used, then moisture absorption is minimized, but the storage duration is limited and requires periodic replacement or regeneration of desiccants
Solution Approach 1:
The patent changes the temperature parameter of the storage environment to below freezing point (typically -40°F to 0°F). This temperature change fundamentally alters the moisture condensation behavior, allowing continuous operation without desiccant replacement. The refrigeration system maintains consistent sub-freezing temperatures that prevent moisture absorption indefinitely, resolving the time limitation of conventional desiccant-based systems.
Solution Approach 2:
The patent uses a refrigeration cycle that continuously replicates the moisture removal function, replacing the need for periodic desiccant regeneration. The refrigeration system creates a continuous low-humidity environment through phase change of moisture on evaporator surfaces, effectively copying and sustaining the drying function without interruption or maintenance downtime.
2Reliability
If nitrogen/dry air purge cabinets are used, then moisture barrier is provided, but already absorbed moisture cannot escape and may move toward electronic components
Solution Approach 1:
The patent changes the temperature parameter to sub-freezing levels, which fundamentally alters moisture behavior. At these temperatures, moisture migrates outward from electronic components to the packaging exterior where it freezes, rather than moving inward as occurs in warmer nitrogen-purged environments. This temperature parameter change reverses the harmful moisture migration direction.
Solution Approach 2:
The patent converts the harmful effect of moisture presence into a beneficial process by utilizing the freezing point of water. Moisture that would normally cause damage at room temperature is instead allowed to migrate and freeze on packaging surfaces at sub-freezing temperatures, effectively removing it from the electronic components while maintaining a simple nitrogen purge barrier.
3Reliability
If baking processes are used to remove excess moisture, then moisture is removed from devices, but component oxidation risk increases and additional equipment cost is required
Solution Approach 1:
The patent applies preliminary action by maintaining continuous sub-freezing storage conditions that prevent moisture absorption in the first place. Electronic components are kept in a preventive low-humidity environment from the start, eliminating the need for subsequent corrective baking processes. This preliminary prevention avoids both oxidation risk and additional equipment requirements.
Solution Approach 2:
The patent inverts the conventional approach by using cold temperatures instead of heat to remove and prevent moisture. Rather than baking components to drive out moisture, the system uses refrigeration to condense and freeze moisture on packaging surfaces, achieving moisture removal through cooling instead of heating, thereby eliminating oxidation risk.
4Reliability
If exposure time is controlled to prevent moisture absorption, then moisture damage is reduced, but tracking and handling complexity increases
Solution Approach 1:
The patent changes the environmental parameters (temperature to sub-freezing and relative humidity to extremely low levels) to create conditions where moisture absorption is negligible regardless of exposure duration. This parameter change eliminates the need for exposure time tracking and handling procedures, as components can be stored and handled indefinitely without moisture damage risk.
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
The refrigerated drying module effectively maintains a low humidity environment, reducing the risk of moisture-related defects in electronic components and minimizing storage downtime by continuously circulating and dehumidifying the air within the storage cabinet.
Implementation Method 1
The refrigerant loop is configured to remove moisture from the air circulated through the air flow loop
Implementation Method 2
collect the removed moisture as ice formed on the surface of an evaporator coil included in the refrigerant loop
Implementation Method 3
The refrigerant loop is configured to remove moisture from the air circulated through the air flow loop
Data Source
AI summary
A refrigerated drying module includes a storage cabinet for storing moisture sensitive devices, an air flow loop configured to circulate air into and out of the storage cabinet and a refrigerant loop configured to remove moisture from the air circulated through the air flow loop. The refrigerated drying module is configured to remove moisture from air drawn from the storage cabinet and collect the removed moisture as ice formed on the surface of an evaporator coil included in the refrigerant loop.