Advancements in Light Emitting Diode (LED) output have allowed the possibility for producing a TV display using LEDs as the source. This paper presents the design of an optical projection system that takes an array of LED sources and scans them onto the screen of a rear projection TV display. A spinning polygon provides the scanning motion.
Protection of high value military equipment against threats requires a robust self defense system. To meet the challenge of defending against a multitude of different types of threats, a fire control system must have the capability to detect, acquire and track, point a mechanisms and launch a device that intercept threats that present different signatures. This paper presents a multisensor optical assembly that has been developed which allows long wavelength, mid-wavelength and near IR energy to be directed to a multisensor suite. This optical assembly is incorporated in the Acquisition, Tracking and Pointing System of the Experimental Small Low-cost Interceptor Device fire control system. In addition to the optical paths the optical assembly contains calibration references for IR two- point calibration. This optical assembly works in concert with a high performance laser pointing system that has a 10,000 degrees per second per second acceleration capability. This combination of systems provides 360 degrees of hemispherical threat acquisition and tracking coverage.
IR materials have very high rates of index change with temperature. These index changes cause thermal defocusing that is an order of magnitude worse than that seen in the visible spectral band, and result in focus shifts usually too rapid to be compensated by housing material selection. The alternative is to actively compensate focus using motorized motions of a lens subgroup. Compensation of a zoom lens is more complex since the required thermal refocusing varies with zoom position. This paper presents a method for thermal compensation that is done in software for computer controlled, stepper motor driven zoom lenses. Compensation can be done to within an arbitrarily small temperature increment.
Narcissus has been understood by FLIR (Forward Looking Infrared) designers for many years. The purpose of this paper is not to elevate the engineering state-of-the-art, but rather, to give an overview of the problem starting with early FLIRs, look at what is being faced by current designers, and to extrapolate future trends.
Conference Committee Involvement (2)
Current Developments in Lens Design and Optical Engineering IV
3 August 2003 | San Diego, California, United States