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US 5,091,718 AGranted
Color-monochrome visual display device
OwnerPaul H. J. Beattyinventor
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OwnerPaul H. J. Beattyinventor
Estimating the term…
A multiple color imaging device such as a beam index CRT (FIG. 3a/b), with red, green and blue phosphor stripes arranged in triplets each defining one color image pixel in the line scan direction having at least the red and green phosphor stripes coated with an electrically insulating barrier layer 38 on which is formed a thin layer 39 of blue emitting phosphor. In color display mode the beam energy is sufficient to penetrate the barrier layer and excite the principal stripe phosphor to give the desired color emission but also excites the blue phosphor, blue emissions being perceived at lower luminance than the red and not detrimental to perceived color purity. In monochrome mode the beam energy is reduced to excite only the blue phosphor. As each stripe is able to emit blue when excited the image resolution for monochrome is increased from color triplet dimensions to individual stripe dimensions or better. The low level of blue emissions is suitable, and preferred, for night viewing of FLIR images, particularly with night vision goggles. Individual phosphor grains may be given a skin of the monochrome phosphor (FIG. 4) or it may be mixed with the principal phosphor without a barrier but with a red/green filter in front of the screen for monochrome operation (FIG. 2).
A display device including a multiple colour visual display device for producing a multiple colour image as a two-dimensional array of image pixels, each pixel being defined by an addressable group of individually energizable three primary colour emitters, each emitter being associated with a physically discrete region of display area and energizable alone or with others to define emission of primary or secondary colours respectively from the group, said display device being adapted to provide a monochrome visual display by emission of radiation of a predetermined monochrome colour, said display device comprising groups of three primary colour emitters affording individual or combined emissions defining said multiple colours, at least some primary colour emitters of each group emitting light in other than said monochrome colour, means for addressing said groups in accordance with formation of a two-dimensional image by energizing the emitters of the groups and, associated at least with the primary colour emitters which emit other than said monochrome colour, an energizable monochrome colour emitter at a lower luminous intensity than the principal colours of the primary colour emitters with which they are associated, whereby each of the discrete regions of said display area may emit said monochrome color, mode control means operable to cause the display of multiple colour images by causing the energization of the emitters of said groups in accordance with the image colour to be generated to produce said principal coloured light at greater luminous intensity than any emission from the monochrome colour emitter associated therewith, and to cause the display of monochrome images by causing the image to be formed by energization of the individual emitters irrespective of their principally emitted colour and to limit light emission from any such emitter energized to that of said monochrome colour.
Dependencies are inferred from the claim text.