Patent GB-809055-A (GB)
Title: Improvements relating to panoramic photographic cameras
IPC: G03B37/00
Filed: 1957-03-08
Abstract: 809,055. Panoramic cameras; optical systems. OPTISCHE INDUSTRIE DE OUDE DELFT, N. V. March 8, 1957 [June 4, 1956; Oct. 2, 1956; Nov. 13, 1956], No. 7827/57. Classes 97(1) and 98(1) A panoramic camera has an optical system substantially shaped as a spherical segment and consisting of part of a spherical shell or of parts of a number of concentric spherical shells of transparent material and a transparent body filling the space inside the innermost spherical shell or part of a spherical shell, and a film support so positioned that its smallest dimension is perpendicular to the end faces of the spherical segment. As shown in Figs. 1 and 2, a lens consists of a spherical segment 2 surrounded by parts 3 and 4 of a spherical shell concentric with the sphere. An image of an object at infinity is formed on the film 6 which is wound from a feed spool 11 to a take-up spool 12 over a cylindrically curved film support 5. The image formed by the lens would normally be toric, and in order to render the image field cylindrical a correcting element with an inner concave toric surface is provided. In the form shown the correcting element also constitutes the film support 5. The shutter consists of a band or tape 7 having a vertical slit 7<SP>1</SP> which is moved in front of the film 6 between rollers 13, 14. A number of radial plates 10, placed at the entrance side of the lens, limit the amount of light admitted to the lens and therefore play the same part as the iris diaphragm of a conventional photographic camera. The lens may be modified by replacing a central portion of the element 2 by a plane parallel plate of the same kind of optical glass as is used for the parts 3, 4. Figs. 5, and 6, show a camera having an angular field of view of 360 degrees. The lens consist of a spherical segment 23 surrounded by a segment 24, and is mounted in a housing 22 which is divided into two parts. The diaphragm plates 27 are mounted in the top part which admits the light, while the film 25 is mounted in the lower part and receives the image. The shutter consists of a number of plates 26, pivoted at 30. In the position shown, the light is prevented from entering the lens. The plates may be pivoted together until they are aligned with the plates 27, whereupon they form part of the stop system. To make an exposure, the plates 26 are rotated through an angle just over 180 degrees. In another embodiment, Figs. 7 and 8, the lens system 31, 32 is designed to accept light from the entire horizon, the angle of acceptance above the horizon being greater than the angle of acceptance below the horizon. The upper part of the housing contains the diaphragm plates 39, and light is admitted by means of a ring 37 which may be moved up or down. An image correcting plate and film support 44 is provided. Film from a feed spool 51<SP>1</SP> is fed by a sprocket and rollers to a chamber 63, where a loop is formed before the film is fed into the camera body, where it passes round the film support 44, which is mounted to rotate with the film. The film, coming off the support, forms another loop in housing 63, and is fed by another sprocket and roller to the take-up spool 51 which is driven by a slipping drive from the sprocket shaft. To reduce reflection at the lower surface at the spherical segment, this surface is made concave as at 35, and a complementary shaped element 36 is cemented to the lens. This element has a refractive index close to that of the elements of the lens 31, 32, and is treated on its underside so as to minimize reflection of light. The camera may be provided with a shutter incorporating a Kerr cell. As shown, in Fig. 9 the optical system, mounted in the camera housing 64, consists of a spherical shell 65 and a liquid 66 which wholly or partly fills the space plate-shaped electrodes 67, 68. The film support 69 is mounted co-axially in a film chamber 70, which is situated under the ring-shaped partitions 71. A cylindrical polarizer 73 is mounted before the entrance surface of the lens system. A similar cylindrical analyser 74 is situated in the film chamber 70 in front of the film support 69. The directions of polarization are at right angles and at 45 degrees with the radial plane. The liquid between the electrodes exhibits the Kerr effect and, when electric potential is applied between the electrodes 67, 68, rotates the claim of polarization so that light can reach the film through the analyser 74. Modifications are described in which the liquid exhibiting the Kerr effect is placed outside the optical system, or between the elements of the optical system. An auxiliary shutter may also be used. Specification 2193/1859 is referred to.