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University of Iowa News Release

 

Nov. 29, 2006

UI Researchers Win $1.25 Million Army Contract For Infrared Technology

A team of researchers from the University of Iowa Department of Physics and Astronomy in the College of Liberal Arts and Sciences has been awarded a three-year, $1.25 million contract by the U.S. Army to develop advanced light projection systems designed to test and calibrate the Army's night vision and thermal imaging technologies.

The UI team consists of principal investigator Thomas Boggess, professor and department chair, and co-investigator and Professor Michael Flatté -- both of whom hold joint appointments in the UI College of Engineering Department of Electrical and Computer Engineering -- as well as Assistant Professor John Prineas. The researchers will develop semiconductor light-emitting devices (LEDs) that emit high intensity infrared light and will incorporate the LEDs into near-megapixel arrays for scene projectors. The scene projectors will behave like television screens, but will display a scene of apparent temperature instead of visible color and will be used to generate scenes for testing infrared cameras and imaging technologies.

Thermal imaging derives from the fact that hot object, such as a person, machine, or armament, emits infrared light that is invisible to the naked eye, but can be detected by night vision or thermal imaging cameras.

According to Boggess, the current state-of-the-art for thermal scene generation relies on arrays of resistors. When current is passed through the resistor at each pixel, the pixel heats up and emits infrared light with properties that are characteristic of the resistor's temperature. By controlling the amount of current passing through each resistor in the array, the thermal image of a scene can be produced. By rapidly changing the current fed to each pixel in the array, one can simulate a dynamic scene, such as a hot object moving through a relatively cool stationary background. The resistor arrays are limited in both how rapidly a current passing through them can be updated and by the maximum temperature that they can simulate. Both limitations are expected to be overcome by replacing the resistor arrays with infrared LED arrays. 

Unlike resistors, the LEDs will not rely on generating heat to produce a thermal image, but instead will directly generate the infrared light characteristic of a given temperature. By developing sufficiently bright infrared LEDs, the researchers hope to simulate much hotter objects than can be simulated through heating a resistor. To maximize the brightness, the LEDs will incorporate state-of-the-art semiconductor nanostructures that are specifically designed for high-efficiency infrared emission. Compared to a hot resistor, the amount of infrared light emitted by the LEDs also can be more rapidly varied, so the scene generated by an LED array can be changed more frequently. The performance improvements that can be realized with the LED arrays suggest that they will produce higher quality infrared images over a wider temperature range than can be achieved with resistor arrays. 

Key collaborators on the project will include Dr. Jonathon Olesberg, assistant research scientist in the UI Department of Chemistry, and Dr. John Lawler of Advanced Thermal and Environmental Concepts in College Park, Md. The UI team will also collaborate with researchers at the University of Delaware and at the U.S. Army Research Laboratory in Adelphi, Md., who are funded separately for their component of the research. All of the UI researchers are affiliated with the UI Optical Science and Technology Center, and the UI portion of the project will be conducted in the Iowa Advanced Technology Laboratories building.

STORY SOURCE: University of Iowa News Services, 300 Plaza Centre One, Suite 371, Iowa City, Iowa 52242-2500.

MEDIA CONTACT: Gary Galluzzo, 319-384-0009, gary-galluzzo@uiowa.edu