Scale illumination with light reflecting edge panels - has reflecting notches as scale symbols which are made visible by light reflected

摘要

Scale illumination is effected using transparent panels in the form of light conductors with a light source (12) at their end faces. The lower face (16) of each totally reflecting panel (11, 21, 22, 23) has one o more notches (17, 28) in the form of scale symbols which become visible by reflecting the light. The nothces (17, 28) are in the form of 90 deg. angle prisms, formed by engraving. The light source (12) at the end is either a glow lamp or a filament bulb.