GB756058A - Improvements in, or relating to, underwater television camera apparatus - Google Patents

Abstract

756,058. Optical apparatus. COMBINED OPTICAL INDUSTRIES, Ltd., and MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Nov. 30, 1954 [Aug. 31, 1953], No. 24060/53. Class 97 (1). Optical apparatus for use in deflecting the light received from a curved window in a watertight casing into the lens system of a television camera in the casing includes a deflecting element rotatable about an axis joining it to the camera and an axis perpendicular to the first and parallel to the deflecting surface. In Fig. 1 the prism 12 is rotatable about the dotted axis and an axis perpendicular thereto and deflects light into a first lens 13 and a slidable field lens 14, which latter varies the magnification. The image is formed on the receiving surface 19 of the television camera by a secondary lens system 15, 18. The prismatic system 16 rotates by half the amount of prism 12 in order to counteract rotation of the image. Lens 15 may be a compound lens or system and lens 18 may be omitted. The window 11 may be a meniscus lens and a positive lens 20 may be included which moves over the window at twice the angular speed with which the prism 12 rotates about its perpendicular axis. In Fig. 3 the deflecting member is a mirror 42 which rotates about an axis perpendicular to the drawing and also about the main axis 49 together with the optical system. The latter comprises a fixed deflector 48 and lens systems 44, 45 and 46 and deflector 50. The deflector 50 may be omitted and the camera 40 with its lens system 41 aligned along axis 47, but it is then necessary for the camera and lens to rotate about axis 49 with the rest of the system. A positive lens 51 may be provided as in Fig. 1. In Fig. 4, a prism 64 rotatable as in Fig. 1 deflects light directly into the objective 62 of the camera 40. The lens system 65, 66 swings around the prism 64 with twice the angular swing of the prism as described above. Specification 416,398 is referred to.