Patent GB-681701-A (GB)
Title: Improvements in and relating to combined kinematographic and television apparatus
IPC: H04N5/84
Filed: 1947-11-13
Abstract: 681,701. Kinematograph apparatus. SCOPHONY, Ltd., WIKKENHAUSER, G., and COOK, G. H. Nov. 13, 1948 [Nov. 13, 1947; Dec. 22, 1947], Nos. 30236/47 and 33881/47. Class 97 (i). [Also in Group XL (b)] In apparatus for recording television pictures on continuously-moving film in which more than one television frame is recorded on the same film frame, an optical device is provided for displacing the images of successive television frames through a distance equal to the distance moved by the film in a frame scanning period iu order to compensate for the movement of the film that takes place in such time period. The television frames recorded on each film frame may be interlaced frames forming a complete picture, or non-interlaced frames where the television and film frame rates differ. In Fig. 1, which shows apparatus for recording two television frames on each film frame, images produced on the screen of cathode-ray tube 11 are projected on to continuously-moving film 10 along a path involving an image displacer 21. The displacer comprises a mirror 25 and a prism 26 carried by a shaft 27 which is rotated intermittently by motor 28 in steps of 180 degrees each, so as to render optical paths 32, 33 alternately effective. Film drive motor 24 and motor 28 are driven in synchronism with the television scanning by generator 29 synchronized from the frame scan generator 17, and the phasing of the motors is so arranged that during one television frame mirror 25 is operative and during the next frame prism 26 is operative. The displacement between paths 32 and 33 is made equal to the distance moved by the film in one frame scanning period. To produce correctly proportioned film pictures the height of the pictures on the screen of tube 11 is increased or reduced by one half, depending whether the frame component of scan is in the same or the opposite direction to the film movement. An alternative image displacer, Fig. 2 (not shown), comprises two prisms formed with a semi-reflecting surface between them and arranged to produce two displaced light paths. A disc shutter renders the paths operative alternately. With this displacer the image produced over one path is inverted and a phase-reversing switch is connected between the frame time base and deflecting coils to reverse the scan in successive frames. Another embodiment, Figs. 5 and 6 (not shown), employs two rhomboid prisms and a drum shutter. Fig. 8 (not shown) illustrates a displacer formed of pairs of mirrors. Each pair of mirrors may be replaced by a prism system or rhomboid prism. Fig. 9 (not shown) illustrates a displacer formed of two prisms and two mirrors. Specifications 589,971, 629,179, 632,817 and 634,854 are referred to in connection with other suitable displacers. Where three displaced light paths are required as in colour television, the displacers shown in Figs. 11 to 15 of Specification 589,971 may be employed, or that shown in Fig. 5 of Specification 632,817, modified to use three lenses. Specification 639,785, [Group XL (b)], also is referred to.