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Large LCDs for dashboards
Displaus news
Low power LCDs provide in-flight emergency instrumentation Liquid crystals provide the display medium in the case of an in-flight failure of aircraft instruments, using equipment developed by Marconi Avionics' Powerplant Systems Division. In case of a major failure of power or instruments, the lowpower LCDs can operate continuously from emergency supplies. They provide essential information to restart an engine in flight and control it while maintaining a safe aircraft attitude. The reversionary displays are to be tested in the Briti~t Aerospace Kingston Borough Division's Avionic Systems Demonstrator Rig. Initially intended for the European ACA fighter, the display is reconfigurable under software control to other aircraft types, and Marconi is bidcling for a range of reversionary displays projects. Civil applications are also envisaged, but not until a consensus has been reached with civil aviation authorities. The two instruments which use LCDs are an engine instrument display and a flight instrument display. The former gives a digital reading of fuel quantity, and analoguedigital displays of engine speed and turbine gas temperature. The latter gives airspeed and altitude in digital form and a symbolic presentation of pitch and roll attitude. The twisted nematic cells are bacldit
with electroluminescent panels and also have front-mounted illumination. Software is driven from a 4 kbyte EPROM in each display. Information is received through high integrity fibre optic data links to make the displays independent of all other electrically signalled cockpit displays. The data can be derived from any high integrity sources which are normally fed by emergency power. These include an aircraft's engine management system and flight control computer where these are the primary means
of control The fibre optic links provide isolation from electromagnetic interference, such as may affect an aircraft's primary insmmtentation. The present ~ are tailored to the demonstrator rig cockpit and are 100 × 80 mmin area. Theiustrument as a whole is 340 ram deep but the display cell itself only accounts for 25 ram of this. This makes many different instrument shapes possible. Marconi Avionics Lid, Airpozt Works, Rochester, Eent M E 1 2 X X DE (634) 44400.
Large LCDs for dashboards
Depending upon the application requirements, the displays can be provided with positive or negative presentation in transnmissive, transflective or reflective versions. Various display segments can be accentuated by introducing additional colours. Integration of the driving circuits into the display allows the number of connections to be cut to seven, independent of the number of segments to be control-
led. Thus complex display systems may be built up comparatively simply. Power dissipation is 0.1 W m -~ with the panel operating at 32 Hz and 8 V. The temperature range is from - 3 5 to 80°C. The 10 pm cell spacing is maintained by spacers • between the 1 nun glass layers.
Car dashboard applications are envisaged for a range of large area liquid crystal displays from AEG Telefunken's technical tube division. The designs can be made to suit specific requirements of particular car models up to a maximum panel size of 210 x 297 ram. Larger displays cart be built up by using these panels in combinations.
180
A E G Telefunken GIIO Lid,Bath Road, Slough, 8erks SLI 4A W, UE (753) 873287.
DISPLAYS. JULY 1984
Low power LCDs provide in-flight emergency instrumentation Liquid crystals provide the display medium in the case of an in-flight failure of aircraft instruments, using equipment developed by Marconi Avionics' Powerplant Systems Division. In case of a major failure of power or instruments, the lowpower LCDs can operate continuously from emergency supplies. They provide essential information to restart an engine in flight and control it while maintaining a safe aircraft attitude. The reversionary displays are to be tested in the Briti~t Aerospace Kingston Borough Division's Avionic Systems Demonstrator Rig. Initially intended for the European ACA fighter, the display is reconfigurable under software control to other aircraft types, and Marconi is bidcling for a range of reversionary displays projects. Civil applications are also envisaged, but not until a consensus has been reached with civil aviation authorities. The two instruments which use LCDs are an engine instrument display and a flight instrument display. The former gives a digital reading of fuel quantity, and analoguedigital displays of engine speed and turbine gas temperature. The latter gives airspeed and altitude in digital form and a symbolic presentation of pitch and roll attitude. The twisted nematic cells are bacldit
with electroluminescent panels and also have front-mounted illumination. Software is driven from a 4 kbyte EPROM in each display. Information is received through high integrity fibre optic data links to make the displays independent of all other electrically signalled cockpit displays. The data can be derived from any high integrity sources which are normally fed by emergency power. These include an aircraft's engine management system and flight control computer where these are the primary means
of control The fibre optic links provide isolation from electromagnetic interference, such as may affect an aircraft's primary insmmtentation. The present ~ are tailored to the demonstrator rig cockpit and are 100 × 80 mmin area. Theiustrument as a whole is 340 ram deep but the display cell itself only accounts for 25 ram of this. This makes many different instrument shapes possible. Marconi Avionics Lid, Airpozt Works, Rochester, Eent M E 1 2 X X DE (634) 44400.
Large LCDs for dashboards
Depending upon the application requirements, the displays can be provided with positive or negative presentation in transnmissive, transflective or reflective versions. Various display segments can be accentuated by introducing additional colours. Integration of the driving circuits into the display allows the number of connections to be cut to seven, independent of the number of segments to be control-
led. Thus complex display systems may be built up comparatively simply. Power dissipation is 0.1 W m -~ with the panel operating at 32 Hz and 8 V. The temperature range is from - 3 5 to 80°C. The 10 pm cell spacing is maintained by spacers • between the 1 nun glass layers.
Car dashboard applications are envisaged for a range of large area liquid crystal displays from AEG Telefunken's technical tube division. The designs can be made to suit specific requirements of particular car models up to a maximum panel size of 210 x 297 ram. Larger displays cart be built up by using these panels in combinations.
180
A E G Telefunken GIIO Lid,Bath Road, Slough, 8erks SLI 4A W, UE (753) 873287.
DISPLAYS. JULY 1984