Keep your distance

Keep your distance

Oisplags neuJs Patents Overlaid L C D s indicate attitude if CRT fails Failure of a C R T multifunction display gives rise to the need for a reliable ...

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Oisplags neuJs Patents Overlaid L C D s indicate attitude if CRT fails Failure of a C R T multifunction display gives rise to the need for a reliable alternative. There are two solid state possibilitiesfor a back-up attitude display as well as the traditional electromechanical alternative which takes up much valuable cockpit space. The fully electronic display could be matrix-addressed, but this is tricky with solid state display technologies. What workers at R A E Farnborough have done in developing a liquid crystal attitude display is to capitalize on the fact that a simple indicator need only to show the two degrees of freedom, roll and pitch. For this they have used two superimposed LCDs, one for each mode. Pitch is indicated with 40 or so strip segments, and roll is shown in

LCD heat leaks blocked A thermal barrier prevents heat used to activate a liquid crystal display from leaking away through the substrate. The display uses a cholesteric LC mixture with a high order parameter pleochroic dye. When smectic phase transitions are incurred, by heating the electrodes in thermal contact with the liquid, two states one light-absorbing, one transparent are set up. A sensitizing voltage applied then completes the addressing to give the required displayed image. The thermal barrier is installed to make sure the majority of the heat is used to activate the display and is not lost. Power consumption is thus low.

European Patents 0 065 447 and 0 065 597, 5M Company, St Paul,

wedge-shaped segments. Addressing is thus greatly simplified. Though 1 o accuracy or so is required normally, the standby instrument can be cruder and use fewer display elements.

UK Patent Application 2 107 059A, RAE Farnborough, Hants GUI4 6TD, UK.

son, PO Box 762, Palm Beach, Ft. 33480, USA.

MIM addressing Simplified representation of two-LCD attitude director indicator

The company uses a r e a d ~ n l y memory to store two groups of control signals. Group one performs write, erase and bulk erase functions as conventionally. The second group does the same but emitting substantially no light. By mixing functions from the two groups and varying their ratio according to the signal on-line a broad range of brightness is made possible. The inventors have also avoided the need for border-sustaining circuits by using a 'distributed conditioning' waveform to all display cells.At a suitable rate 120 Hz is suggested - discharge is obtained with no m e m o r y loss.

UK Patent Applications 2 102 177.2102179A, Interstate Electronics Corporation, 707 E Vermont Avenue, PO Box 3I 17, Anaheim, CA 92803, USA.

M N 55133, USA.

Plasma brightness tamed Improved brightness control on a c plasma panels is possible using a technique from Interstate Electronics.

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silvered internal surface and a transparent face opposite. The mirrored side splits the CRT image from the electron gun so that part ends up on the screen and part outside the tube, within the unit's outer cabinet. The second part is focused onto a reconstructing plate where it is joined by a beam of laser light. The combined image is then presented through a magnifying lens as a three-dimensional picture to the viewer. US Patent 4 ,~59 758, G. Teacher-

Holographic TV An inventor in Palm Beach, Florida, claims to have devised a holographic television set. The design is based on a CRT, but the tube has one fully

Metal-insulator-metal (MIM) resistors are used in a liquid crystal display assembly from Suwa Seikosha. The MIM non,linear resistive devices comprise a metal thin film with an anodized oxide surface layer. A second metal film on the oxide completes the MIM sandwich. Each picture element on the display has a pair o f the MIM devices associated with it, connected in such a way as to yield a more or less symmetrical I-V characteristic. The MIM resistors may thus be connected in series or parallel and opposed to one another. UK Patent Application 2 091 468A,

Suwa Seikosha KK, 3.4, 4-chome, Ginza, Chuo-ku, Tokyo, Japan.

Keep your distance One answer, if a somewhat Procrustean one, to the problem of ideal viewing distance for using a VDU could come from a Mr M. Wang in Talwan. He has filed a UK patent application for a device which produces interference on a TV screen when someone gets too near. Only by resuming the correct distance will the interference go away.

M.S. Wang, 1st Floor, 29 Ming. Hsi Street, Shih-lin, Talpei, Taiwan.

DISPLAYS. JULY 1983