Anordnung zur steuerbaren Ablenkung eines Lichtstrahls

1,220,972. Light deflectors. INTERNATIONAL BUSINESS MACHINES CORP. 24 Oct., 1968 [18 Nov., 1967], No. 50504/68. Heading H4F. A light deflector comprises a switchable electro-optic half-wave plate 6, Fig. 2, selectively operable to change the plane of polarization of a linearly polarized light beam 1 by 90 degrees, and a deflecting element 40 constructed of a plurality of transparent layers, adjacent layers having different refractive indices, and positioned so that the light beam is incident at Brewster's angle and is thus transmitted through or reflected from the deflecting element depending on its plane of polarization. The reflected light beam is aligned with the original direction of the light beam by means of reflecting element 50. In the arrangement as shown in Fig. 2 including multi-layer deflecting elements 40-46, and reflecting elements 50, 56, by selectively energizing electro-optic half-wave crystals 6, 26 and 36 the light beam may be brought to any one of the positions 1f-1n. In a further arrangement, Fig. 3 (not shown) the deflecting elements 41 and 42, and the reflecting elements 51 and 52 of Fig. 2 each comprise one larger deflecting element and reflecting element, respectively. Each deflecting element comprises a ground glass plate having alternate 1 micron layers of titanium dioxide and silicon dioxide placed thereon. The reflecting elements may be curved.