| 摘要 |
<PICT:1086133/C4-C5/1> A display device for providing back-lighted black-background illumination of an object, e.g. clock hands and figures 14, 16, comprises in order a light source, a first filter 26 (e.g. passing blue light), a luminescent object 14, 16 and a second filter 30 (e.g. passing green, amber and red light) there being no overlap in the visible pass-bands of the filters and the luminescent material being such that it is activated by light passing the first filter, and emits light passing the second filter. The light source may be sunlight or a discharge or electroluminescent lamp, and the luminescent material may be mounted on either filter, or on an intermediate support (e.g. using magnets). The arrangement is described in relation to clocks: display panels, Figs. 4-8, 20-22 (not shown): co-ordinate plotters, Figs. 9, 10 (not shown): moving belt displays, Figs. 18, 19 (not shown): and instrument panels and automobile or aircraft dashboard displays, Figs. 23-29 (not shown). Features involved may be edge lighting of luminescent panels, Fig. 10, not shown): combination of black-field displays with luminescent illuminated-field displays of two or three dimensional objects, Figs. 12-17 (not shown): displays with luminescent bubbling liquid, Fig. 22 (not shown): scales with different ranges luminescing in different colours, e.g. speedometers, Fig. 27 (not shown). The first filter material may be a frit of blue acrylic resin or of blue-glass particles, beads or flakes. The objects illuminated may be letters, numbers, scales, pointers, indexing means, liquids, sculptures, silhouettes or flowers. |
