Gary R. Knowles

Dual tunable Fabry-Perot spectrally agile filter

Two unconventional Fabry-Perot interferometer cavities are used in series to permit transmission of both wide and narrow spectral bands in the infrared. The use of two cavities, in series, blocks unwanted harmonics and effectively extends the free spectral range of the device. The regime of operation covers the middle- and far-infrared spectra, as well as portions of the near- and extreme-infrared. Very small cavity spacings are used to produce a very wide-band transmission window when the device is operated in the zero-order mode. Tuning the device with a closed-loop capacitive control system produces vari-able cavity spacings in higher-order modes, resulting in variable transmission bandwidths over a large spectral range. The design and fabrication issues for two-cavity Fabry-Perot interferometers are discussed, and theoretical perfor-mance and test results are presented for two infrared devices.

Combat vehicle visualization system

A combat vehicle visualization system is described that enhances the situation awareness of the vehicle commander. The system consists of a 360 degree(s) panoramic sensor, a gimbaled 8 - 12 micrometers infrared sensor, and a helmet-mounted display with head tracker. The helmet-mounted display can display the fused sensor data to aid the commander in vehicle maneuvering and threat acquisition while buttoned up. It can also display situation awareness information down-loaded from the tactical internet while standing in the hatch. Construction and operation features will be described.

Miniature flat panels in rotary wing head-mounted displays

A number of programs are attempting to validate the advantages and disadvantages of miniature flat panel displays compared to CRTs for use in rotary wing helmet mounted displays. This paper will explore the unique requirements of rotary wing helmet mounted displays and will assess the applicability of miniature flat panel displays for meeting these requirements. Remaining technical challenges will be discussed and potential solutions identified.

Dual Tunable Fabry-Perot: A New Concept For Spectrally Agile Filtering

Honeywell has developed a spectrally agile infrared filter based on the dual tunable Fabry-Perot (DTFP) concept. A DTFP transmits broad or narrow spectral bands which are tunable over a large spectral range. Harmonic spectral transmission can be eliminated by maintaining staggered cavity orders. Several DTFP filters have been fabricated and tested. A closed-loop, capacitive control system is used to adjust plate alignment and spacing. DTFP transmission greater than 0.8 and drive and stabilization times of less than 4.0 milliseconds have been demonstrated. DTFP design considerations and experimental performance data will be discussed.

Helmet-mounted display integration using flat panel image sources

The advent of flat panel display technology has created new thermal challenges for the integration of the image sources into helmet mounted displays. Each of the leading display technologies, when driven to high brightness, leads to heat dissipation challenges. For the higher brightness displays it will be shown that active cooling systems are necessary. Further discussions suggest that display peak brightness and resulting heat output may be reduced to mitigate some of the thermal control problems.