As a supplier to U.S. and international defense and space agencies for more than 35 years, II-VI Marlow offers a seasoned team of engineers and scientists who develop superior quality solutions, tested and qualified to defense/space requirements.
II-VI Marlow's distinctive space qualification procedure allows us to design, fabricate and test thermoelectric coolers (TECs) for space applications and diverse extreme conditions. The process includes TEC design and documentation, thermoelectric material processing, TEC assembly operations and TEC testing.
II-VI Marlow manufactures in both the U.S. and Asia. Due to International Trade and Arms Regulations (ITAR) and Department of Commerce restrictions on products supplied to the U.S. government, II-VI Marlow maintains controlled-access engineering and manufacturing facilities in Dallas, TX, to support our government contract business.
Read more on our defense, space and photonics applications:
Unmanned Aerial Vehicles allow for successful reconnaissance without endangering airmen or ground soldiers. II-VI Marlows' rugged thermoelectric cooling devices of minimal size, weight and power ensure maximum endurance and performance of UAV image sensors in remote environments.
In addition, II-VI Marlow offers thermoelectric power generators that convert heat from a combusted battlefield fuel to electrical power for electronics vital to UAV aircraft operation. These thermoelectric power sources eliminate down time typically needed to recharge batteries, increase vehicle readiness and enable UAV’s to operate 4-5x’s longer than a battery powered source.
Environmental circumstances and recent developments in detector technology require thermal management for equipment to operate at extreme temperatures. II-VI Marlow specifically formulated and developed a family of low-temperature thermoelectric materials to address this requirement.
These materials allow the II-VI Marlow designer to develop coolers that match your application size, weight and power conservation requirements while providing reliable thermal stabilization at extreme temperatures. II-VI Marlow coolers in this program, for example, provide temperature stabilization at 140 Kelvin for various space applications. II-VI Marlow continues to drive material research and development capability to ensure the highest performance on low-temperature thermoelectric materials.
Examples of detector and sensor cooling and temperature stabilization include:
Star Tracking Systems
Celestial navigation is employed widely in missile guidance, satellite attitude determination, aircrafts and spacecrafts, and is performed by Star Tracking Systems. A Star Tracking System uses stellar references obtained by various narrow-field-of-view "Canopus Trackers" cameras to update inertial references. II-VI Marlow provides space-qualified thermoelectric coolers to cool detectors and increase their sensitivity.
Thermal Imaging Cameras
A Thermal Imaging Camera contains a sensor that reacts to infrared energy from surrounding objects and coverts this “thermal signature” to a visible image. Thermoelectric coolers (TECs) stabilize the temperature of the infrared detector, ensuring the camera produces the best image from external photonic sources. These thermal images, for example, allow firefighters to see in dense, smoke-filled environments to identify hot spots, thereby revolutionizing firefighting methods and improving firefighter safety.
Infrared/Visible Detectors, CCD Sensors
Infrared/Visible spectrum detectors and CCD sensors have negative temperature performance coefficients – exposure to cool temperatures reduces noise generation characteristics and improves sensitivity/performance. II-VI Marlow provides thermoelectric coolers (TECs) that use single-stage cooling for near-room temperature operation through six stages cooling for operation to 170 Kelvin (-103°C).
Hubble Space Telescope Application
II-VI Marlow has provided thermoelectric coolers (TECs) for the Hubble Space Telescope’s (HST) initial Wide Field Planetary Camera (WFPC 1) and all subsequent WFPC 2 and 3 upgrades. These coolers enable detectors to meet specified performance parameters necessary to view the myriad of extraordinary stars, galaxies and other astronomical bodies and formations existing throughout our universe. In addition, II-VI Marlow has designed, developed, fabricated, space-qualified and delivered single-stage and multi-stage thermoelectric coolers over the lifetime of the Hubble for various instruments. Each design met stringent cooling and environmental endurance requirements
II-VI Marlow offers optimized and high reliability solutions specially designed to meet customer's technology requirements.
A TTRS is a thermoelectric cooler assembly providing a temperature-controlled, radiometrically uniform, high-emissivity surface used to calibrate infrared detector arrays. TTRS assemblies are either hermetically sealed or open devices consisting of a thermoelectric cooler, a high-emissivity, thermally uniform emitting surface and a temperature-sensing device. Typically, the TEC mounts to a TO-3 or TO-8 header or a custom-designed mounting bracket.
TTRS’s provide correction for responsiveness and gain differences via a two-temperature (color) correction. In scanning systems, this is performed using two TTRS devices that are included in the optical field of view. In starring systems, a single TTRS is inserted into the optical field of view, and the temperature is rapidly changed to perform a multi-color correction.
II-VI Marlow supplies a wide variety of both custom and catalog TTRS assemblies. These TTRS’s are currently used in both starring and scanning systems and include hermetically sealed and unsealed units.
II-VI Marlow has experienced engineers and other resources to address the design and development issues inherent to TTRS systems. TTRS’s can be provided with custom-mounting brackets, wiring harnesses, and flex circuit assemblies to meet the ANSI/J-STD-001 specification. II-VI Marlow also provides in-house testing, including infrared camera uniformity testing, for all TTRS products.
Because lasers are not 100% efficient, waste heat is generated during the lasing process. Heating of the laser can result in wavelength shift, a compromise in reliability, and ultimately failure of the laser system.
Thermoelectric cooling assemblies are ideal for removal of waste heat and laser temperature stabilization. II-VI Marlow has extensive experience in laser temperature stabilization for military applications. This includes stabilizing the diodes used as pump sources for laser designators as well as the lasing medium (nonlinear crystals, for example).
When a soldier or pilot becomes overheated, their mental and physical reactions can be compromised. Extended exposure to hot environments, in the desert for example, can also be dangerous.
Thermoelectric cooling assemblies chill fluid, which is circulated throughout a vest worn by the soldier or pilot. The system effectively cools the soldier or pilot, ensuring their mental acuity and physical reactions remain consistent despite harsh temperature environments. Most recent thermoelectric assembly developments have resulted in portable cooled air systems. These systems give the wearer more freedom of movement and the ability to complete normal mission functions in extreme hot or cold environments.
Active matrix liquid crystal display (AMLCD) panels display data, images, symbols and text for human-readable screens. Commercial aviation serves as one of the many applications for this technology. The ability to clearly view instrumentation in varied lighting conditions is critical to safe operation of the aircraft. Thermoelectric modules provide an effective automated means of contrast and brightness adjustment to improve instrumentation readability in bright daylight or pitch darkness.
The thermoelectric cooler (TEC) makes contact with the tube through a "cold shoe" that controls the temperature of a spot on the tube. By increasing and decreasing the temperature of that spot, mercury condenses or vaporizes on the spot with the change in temperature. More vapor in the tube causes the tube to glow brighter. An automatic gain control senses the amount of ambient illumination and controls the thermoelectric cooler. Above the clouds, where sunlight is particularly bright, the AMLCD requires maximum brightness; at night on the ground, it needs little.
The uncooled infrared sensor is a thermal detector that can operate at an elevated temperature without the need for temperature reduction to enhance its responsiveness, detection and other radiometric characteristics. These detectors use materials that can operate at or above room temperature without degradation. The detector senses a change in conductance or some other temperature-dependent parameter and must be temperature-stabilized at or near the selected operating temperature to achieve optimal performance. Depending on the ambient temperature, the thermoelectric cooler either heats or cools the sensor to the desired operating temperature.
II-VI Marlow provides both stand-alone thermoelectric coolers and thermoelectric coolers integrated with a ceramic package where the package serves both as the bottom ceramic to the TE cooler as well as the base of the hermetic package for these applications.
As system technology advancements increase the compactness and heat load density of electronic equipment, the need for capable thermal management becomes more critical. Whether the equipment is housed in a laboratory facility or in a remote location, the requirement for an adequate and reliable cooling solution is the same. A thermoelectric cooling solution provides for customization of size, shape and thermal range, with the added advantage of long-term reliability and without the required maintenance of a compressor system.
The II-VI Marlow thermoelectric cooling system uses state-of-the-art power control methods with its integral power supply controller. Based on pre-programmed logic, the variable controller senses temperature fluctuation detected by a temperature sensor. Based on PID (proportional integral differential logarithm) logic, this method avoids a power depleting “on”/“off” approach, and instead maintains a stabilized temperature. This control method increases the life of the thermoelectric system and provides a conservative energy solution, thereby enhancing green feature capabilities.
This thermoelectric cooling system specifically meets the challenges associated with a higher heat and humidity environment, requiring a high heat pump and low ∆T solution. Conditions within a sub 500W and 15-30° ∆T range are typically ideal for a thermoelectric equipment enclosure solution.
The latest II-VI Marlow equipment enclosure cooling solution is smaller and lighter weight than conventional thermoelectric cooling systems. It also requires less input power, improves efficiency and ∆T performance, and creates less noise. The new thermoelectric system, a patent pending thermoelectric design, exhibits these capabilities. In addition, the SLIC system is designed with ruggedized components to allow system survival and high performance in the most challenging outdoor environments.
II-VI Marlows' energy harvesting solution can capture heat from a battlefield fuel burner to power a fan to circulate heat through the tent. This system eliminates the need for batteries, large generators, and any other requirements of a dependent energy source. The II-VI Marlow thermoelectric generator is self-powered and self-sufficient, requiring no maintenance for its lifetime. All thermoelectric generator solutions and sub-assemblies are scalable, thereby enabling the circulation of heat across large areas. II-VI Marlow energy harvesting solutions allow soldiers in isolated, cold climates access to a reliable source of heat while providing energy savings over the current system.
II-VI Marlow's thermal reference sources provide real time calibration of infrared detectors, by offering a radio metrically uniform, blackbody source that one can set to a range of temperatures. Such technology requires a controller that achieves the target temperature range, based upon the changes detected by a thermal sensor. This system, located within an image sensor device, provides the thermal management necessary to record video/imagery in daylight or thermal images at night.
While competing technologies do not demand temperature stabilization, sensors equipped with a thermoelectric system provide higher image sensitivity and clarity. II-VI Marlow offers rugged thermoelectric cooling solutions of minimal size, weight and power output to ensure maximum endurance and performance of image sensors in remote environments. II-VI Marlows’ thermal reference sources meet safety flight certification requirements.
II-VI Marlow also offers power generation solutions for small UAVs, beyond image sensing. In this process, thermoelectric power generators convert heat from a combusted battlefield fuel to electrical power for vehicle propellers, radio and navigation systems, and other electronics vital to aircraft operation. These thermoelectric power sources can be 4-5x more energy dense than a battery, enabling battery powered UAV’s to operate 4-5x’s longer. Furthermore, this technology recharges batteries by simply re-filling a fuel tank, thereby eliminating down time typically needed to recharge and increasing vehicle readiness capability.
Unattended Ground Sensors (UGS)
Ground sensors spread along a forward edge of the battle area (FEBA) provide critical intelligence to military personnel, while reducing human exposure during surveillance and reconnaissance missions. Current ground sensors use battery power and require regular replacements to ensure operability. In addition to the replacement expense, personnel deployed to maintenance the sensors are continually at risk.
II-VI Marlows’ high-temperature thermoelectric generators enable a thermoelectric power source solution for perimeter surveillance that extends the operating time of these critical sensors. This technology reduces the cost of battery replacements and risk to military personnel when sensors deployment in hostile areas is required. These thermoelectric devices can power an unattended ground sensor by converting heat produced by a battlefield ready JP-8 fuel burner into electrical power, an energy source 4-5x denser than battery power. This capability enables the sensor to operate 4-5x’s longer between battery charges; thus proving ideal for battlefield scenarios.
Robotics (Unattended Ground Vehicles, UGV)
Unattended ground vehicles have the potential to significantly minimize human exposure along enemy lines. A remote control robotic device designed to enter high-risk areas and gather vital data regarding enemy capability can reduce the need for human reconnaissance and surveillance. Existing robots use battery power, an energy source that demands regular replacement and maintenance.
The II-VI Marlow thermoelectric solution will power unattended ground vehicles for extended periods of time. Prior to activation, the thermoelectric device located within a robot will harness heat from a battlefield ready fuel burner (JP-8). The power generation devices will then convert the heat to electrical power for the robotic device; generating an energy source 4-5x denser than its battery operated counterpart. This process eliminates the need for transport of additional battery supplies and enables the surveillance equipment to maintain power longer than a battery or other energy source. II-VI Marlows’ commitment to quality and testing- specifically for extreme, rugged conditions-meets the standard requirements of the defense industry.
Soldier Wireless Electronic Power
Soldiers on the battlefield currently carry a battery supply for wireless equipment operation, due to the regular need for replacements while in the field.
II-VI Marlow power generation technology utilizes the heat from a portable battlefield fuel burner to provide electricity for soldier equipment. This thermoelectric solution substitutes the need for a surplus battery count with a portable power source: a small burner and a lightweight, rugged power generation system. Energy produced through this system can provide the electrical power needed to charge a cell phone and other tools necessary for survival in remote areas. This method of power generation provides a self-powered, low maintenance and durable energy source designed to increase soldier mobility.
Note: All II-VI Marlows’ thermal reference sources meet the standard requirements of the defense industry.
The need for remote, localized power throughout the battlefield to run a host of electronic devices and equipment for soldier safety, situational awareness, comfort, and combat superiority is ever growing. Many of these devices are battery powered. Due to the regular need for replacements while in the field, the logistics and added weight requirements for US military personnel has become overly burdensome.
II-VI Marlow power generation technology can use the heat from combusted battlefield fuels to provide electrical power for soldier equipment, substituting the need for a surplus battery count with a portable power source: a small burner and a lightweight, rugged power generation system. This method of power generation provides a self-powered, low maintenance, and durable energy source designed to increase soldier mobility.