By Chris Chinnock
ALPHARETTA, Ga. - Avionics designers are set to replace more cathode ray tube (CRT) displays on the U.S. Army Boeing AH-64 apache attack helicopter with new active-matrix liquid crystal (AMLCD) displays.
This time the switch from CRTs to flat panels involves an overhaul of the Apache`s Target Acquisition Designation System/Pilot Night Vision System (TADS/PNVS) from the Lockheed Martin Electronics & Missile Systems division in Orlando, Fla. Display engineers from L-3 Display Systems of Alpharetta, Ga., will supply the AMLCD modules.
The TADS/PNVS now has two CRT-based displays and direct-view optics. One CRT is a high-brightness, low-resolution display that enables the Apache`s co-pilot/gunner to steer toward targets and to skew his direct-view optics toward areas of interest. He looks down into the direct-view optics for fine target acquisition. At night, he views images from a forward-looking infrared (FLIR) sensor on the high- resolution, low-brightness CRT.
Lockheed Martin avionics specialists are redesigning much of this system. They will scrap the direct-view optics and two CRTs and replace them with one AMLCD flat panel for viewing daylight and FLIR images. Lockheed Martin designers will mount the CRT directly in front of the co-pilot/gunner.
Requirements for this display included sunlight readability, high resolution, and many level of gray scale. The old TADS/PNVS configuration required two CRT displays because one of sufficient resolution and sunlight readability simply was not available.
Designers at L-3 Display Systems won a $3.8 million contract to deliver the new AMLCD for TADS/PNVS. The 5-by-5-inch L-3 flat panel has resolution of 980 by 980 pixels, offers 256 levels of gray scale, and has two modes of operation: one for sunlight, and the other for night vision. It enables Apache crewmen to view video, FLIR images, and symbology all on the same display.
Engineers at dpiX in Palo Alto, Calif., will fabricate the AMLCD glass, while experts at Planar Advance in Beaverton, Ore., will add driver electronics, thermal management, and ruggedization.
This module is similar to a color display that the dpiX/Planar team is supplying to the Royal Australian Air Force leaders for their Hawk 100 lead-in fighter. That display however, features a RGBG quad-color-pixel arrangement.
For the TADS/PNVS system, the LCD cell structure remains essentially the same, but dpiX/Planar experts remove the RGBG color filters for monochrome operation, thus providing 960 by 960 pixels of resolution. Planar must use different drive electronics for the monochrome display.
The U.S. Army Boeing AH-64 Apache attack helicopter, pictured above, will receive one active-matrix liquid crystal display to replace two cathode ray tubes and an optical sight.
