GB219438A - Improvements in or relating to reflectors - Google Patents

Abstract

219,438. Miethe, A. May 17, 1923. Reflectors; lenses. - A reflector, more particularly adapted for use in kinematographic projection, has a cooling chamber placed between an electric arc and the reflecting-surface, the arc being in front of the chamber, so that the latter is traversed twice by the rays of light from the arc, the reflecting-surface sometimes being brought into optical contact with the rear wall of the chamber. In the form shown in Fig. 1, the reflecting-surface a forms the rear wall and a transparent glass b forms the front wall of the cooling chamber which may be filled with water or a substantially colourless heat-absorbing solution, such as a ¢ per cent copper-iron sulphate solution, circulation being maintained by an inlet pipe e and an outlet pipe f. The reflecting- surface a may be spherical and the glass front b may be flat as shown, or it may be so shaped as to reduce or entirely correct the spherical aberration of the spherical reflecting-surface. The carbons g, h are disposed in the axis of the reflector, the negative carbon g being carried through a water-tight duct d in the cooling- chamber. In the form shown in Fig. 2 the effect of an ellipsoidal reflector is obtained by combining a paraboloidal reflecting-surface a with a spherical transparent refracting-surface b so as to form a lens-like body, which is preferably filled with a cooling liquid.