| 摘要 |
The device for illuminating an original in a photographic colour copier has a lamp housing, which consists of a mirror (28) and light source (29), and a device (1) for continuously colouring the beam path in front of the plane of the original by means of a plurality of colour filters (2-27) which are arranged behind one another and can partly be moved into the beam path. In this arrangement, the filter of a colour is divided into at least two subfilters of which each can be swivelled about one axis each, fixed to the device, by means of drive members. The mirror is constructed as an ellipsoid (28) at whose first focal point (F1) the filament of the light source (29) is arranged. The device (1) is inserted in the beam path of the ellipsoid (28) in a plane perpendicular to the optical axis (30) and situated at a distance (A) before or after the second focal point (F2) of the ellipsoid (28) such that the opening (1a) of the device (1) is essentially illuminated and the central region of the device (1) is situated in the shadow of the light source (29). The distance (A) of the device (1) from the second focal point (F2) has the formula: <IMAGE> d being the diameter of the opening (1a), b the minor semi-axis of the ellipse on which the ellipsoid is based, and f the focal length of the ellipse. <IMAGE>
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