| 摘要 |
1354617 Scanning cameras EASTMAN KODAK CO 28 May 1971 [15 June 1970] 17750/71 Heading G2A In a scanning camera, in which a viewed scene is imaged, increment by increment, through a lens system and a slit aperture on to a moving film strip, the axis about which a movable element of the scanning means pivots passes through the first principal point of the lens system. This arrangement reduces the "smearing" effect due to the apparent movement of the effective viewpoint of the lens. As shown, the scene viewed is reflected from a mirror 22 which can pivot on a shaft 23, through a lens system 24, and reflected again from a fixed mirror 21 to pass through an aperture slit 15 on to the film sheet 12. The sheet is transported in the direction 13 by sprockets 17 driven by a motor 19. A lever 27 on a fixed pivot 28 has a nose 29 at one end which follows a cam 26 fixed to one of the sprockets 17. The other end of lever 27 bears against the end 31 of an arm 32 fixed to the top end of the mirror shaft 23. Shaft 23 is biased anti-clockwise, so that nose 29 is maintained in contact with the cam 26. Thus by shaping cam 26 to an appropriate profile a predetermined relationship may be established between the linear movement of film sheet 12 and the angular movement of mirror 22. The lens 24 is a telephoto lens of the type shown in Fig. 3, having a positive element 45 and a negative element 46. These are combined so that the principal points P 1 and P 2 are located forwardly of the lens elements (as shown) in Fig. 3, so effecting an increase in the focal length F. The inventive step consists of locating the first principal point P 1 at or near the axis of mirror 22. The arrangement also enables the camera to have a more compact structure, and also a smaller mirror 22. |
