Abstract: Arrangement for collecting and emitting light via defined surface areas (25) in order to create a slide. The arrangement consists of a number of transparent plate elements, collector plates (12-15), which are designed to receive incident light at one or more of their surfaces, collector surfaces (17-22), and to emit the received light at one or more of their other surfaces, emission surfaces (28). The collector plates consist of fluorescent material designed to convert received ultraviolet light to visible light. The arrangement comprises a plate (3) which forms a carrier for the slide which is to be presented. The plate elements (12-15) are set transverse to the carrier plate with their light-emitting surfaces (28) bearing against the rear side (29) of the carrier plate. The light-emitting surfaces (28) are situated in strip-shaped intermediate spaces between opaque parts (24) of the carrier plate.

Abstract: Device for indicating the angular position between a first part and a part which is rotatable relative to the first part. Each of these parts exhibits a grating (15, 16) consisting of a pattern which, in each grating, comprises opaque lines separated by interspaces, the gratings together being arranged to provide an easily readable moire pattern which indicates whether the opaque lines in the one grating are at a certain position relative to the opaque lines of the other grating. The interspaces of each grating (15, 16) exhibit mutually differing widths, with a width which gradually increases over the height of the one grating (15) in a direction transverse to the longitudinal direction of the interspaces and a width which gradually decreases over the height of the other grating (16) transverse to the longitudinal direction of the interspaces and in the same direction.