Thermally integrated laser/FLIR rangefinder

摘要

A forward looking infrared (FLIR) energy imaging device has been found to include components which are required by the receiver portion of a long-wavelength rangefinder. For example, the FLIR collecting lens system which focuses energy from a scene onto a sensitive, cooled detector array duplicates the function which must be performed by the laser rangefinder receiver. Thus an integrated laser/FLIR rangefinder comprises a laser transmitter for illuminating a target, and an IR energy optic channel having a FLIR for receiving IR energy and producing a visible image representative thereof, said FLIR including an afocal lens system for collecting and focusing energy from the target and energy from the laser return having a wavelength compatible with the band pass of the IR optics and detector onto a cooled sensitive detector. In one embodiment the cooled detector is one of the center detectors of the FLIR detector array, in another embodiment the laser return energy collected by the FLIR afocal lens is reflected by a reflecting chopper, inserted in the FLIR optical path during the dead time generated for scan interlace, to a detector other than one of the center detectors in the array and unused by the thermal imager, or in still another embodiment the laser return detecting detector is a detector other than the cooled detector's of the FLIR detector array and includes a separate cooler. The laser return detector is connected to a laser preamplifier for producing a laser return signal for the laser rangefinder electronics. The laser electronics receives a laser firing signal for starting a counter whose count is latched by the output signal of the laser burst detector amplifier. Ranging information is derived from the count.