GB1087072A - Indicating instrument illumination - Google Patents

Abstract

<PICT:1087072/C4-C5/1> An indicating instrument 1 with a movable indicating member 5 viewable through aperture 3 has electroluminescent lamp 6 so arranged that light therefrom reaches the indicating member via a surface of peripheral wall 4 of the aperture, the surface extending in front of the indicating member plane and being inclined inwardly towards the indicating member so as to illuminate it from the front. In another embodiment the aperture is in a transparent panel having an opaque outer layer and reflecting inner layer, the lamp being in the form of a ring around the aperture near the inner face of the panel; if the lamp is near the outer face of the panel, the reflecting layer is not necessary, the light passing directly through the bevelled edge of the aperture. In a further embodiment a plate in front of the dial has a central aperture with a bevelled edge, the lamp lying on the frustoconical surface surrounding the bevelled edge and shining directly on the dial. In another embodiment the lamp lies behind the dial in a block of transparent material having a collar around and extending in front of the dial and with an inwardly directed bevelled reflecting surface so that light from the lamp passes into the collar and is reflected on to the pointer, the dial markings are etched, engraved or embossed. Finally a combination of the latter two embodiments illuminates pointer and dial respectively. Instruments employing these means of illumination, include those with rotary needles, rotating cylinders, discs and dolls eyes indicators.