Bi-stable Solenoid Shutter for Cryogenic Aperture Control
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Solution Overview
Problem
Imaging devices operating at cryogenic temperatures in ultra-high vacuum environments face challenges with temperature stability due to friction and heat transfer from drive mechanisms, leading to significant wait times before imaging can be effectively used, as prior art devices with piezo electric drives are not suitable for such conditions and experience thermal instability.
Innovation Solution
A shutter assembly utilizing a bi-stable solenoid motor with thermally isolated actuators and shutter members, maintaining thermal contact with a conductive housing to stabilize temperature, and a controller to manage motor velocity and parameters for precise aperture control, reducing thermal fluctuations and enabling immediate use after aperture changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If piezo electric drives are used to position the shutter, then the shutter can be mechanically configured to have two or more apertures, but the friction generates particles and causes thermal instability in ultra-high vacuum and cryogenic environments
Solution Approach 1:
The patent replaces piezo electric drives with a magnetic drive system that uses magnetic fields to position the shutter blades without mechanical contact. This eliminates friction and particle generation while maintaining the ability to configure multiple aperture positions, solving the contradiction between mechanical configuration capability and thermal stability in cryogenic vacuum environments.
Solution Approach 2:
The patent introduces magnetic fields as an intermediary to transfer force to the shutter blades without direct mechanical contact. The magnetic drive system uses magnetic attraction and repulsion to move and hold the blades at desired positions, eliminating the need for mechanical friction-based drives and thereby preventing thermal instability and particle contamination.
2Adaptability or versatility
If interleaved iris design with multiple ceramic coated blades is used to transfer heat, then the shutter can be mechanically configured, but the ceramic coating makes the blades poor thermal conductors causing large temperature changes
Solution Approach 1:
The patent replaces the mechanical interleaved iris design with a magnetic drive system that positions blades without requiring them to be forced together for heat transfer. The blades can be made from materials with good thermal conductivity, and their positions are controlled by magnetic fields rather than mechanical forcing, eliminating the thermal conduction problem caused by ceramic coatings.
Solution Approach 2:
The patent changes the material parameter of the shutter blades from ceramic-coated (poor thermal conductor) to materials with good thermal conductivity. The magnetic drive system enables position control without relying on thermal conduction through forced contact, allowing the use of thermally conductive materials that maintain stable temperature during positioning.
3Adaptability or versatility
If the shutter is mechanically configured to change aperture size, then different fields of view and wavelengths are supported, but the wait period before imaging exceeds 10 minutes due to temperature stabilization
Solution Approach 1:
The patent replaces mechanical friction-based drives with a magnetic drive system that positions shutter blades without generating significant heat. This eliminates the thermal instability that causes long wait periods, allowing the imaging device to be used immediately after aperture configuration while still supporting multiple fields of view and wavelengths.
Solution Approach 2:
The magnetic drive system positions the shutter blades accurately and holds them stable without generating heat that would require stabilization time. By eliminating the thermal transient problem, the system allows imaging to begin immediately after configuration rather than requiring a 10+ minute wait period for temperature stabilization.
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 solution provides thermal stability to the shutter assembly, allowing for immediate use of high-definition IR sensors without significant wait times, as the bi-stable solenoid motor maintains temperature within 10 Kelvin, overcoming the limitations of prior art devices by being vacuum stable and reducing friction-related issues.
Implementation Method 1
a bi-stable solenoid motor having a motor member, the solenoid motor configured to drive the motor member between a first position and a second position
Implementation Method 2
maintaining thermal contact with a conductive housing to stabilize temperature
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A device (10) operable in a ultra-high vacuum and in a cryogenic environment. The device has bi-stable solenoid motors (18) configured to drive a shutter assembly (12) defining an aperture (15) having a first shape when the motors are each disposed in the respective first position, and wherein the aperture has a second shape when the motors are each disposed in the respective second position. Actuators (30) responsive to the motors are thermally isolated from the cryogenic shutter assembly except when the motors position the shutter assembly to change a shape of the aperture. The device is suitable for use in FLIR and other thermally sensitive devices.