| 摘要 |
560,008. Optical projection apparatus. KODAK, Ltd. Sept. 11, 1942, No. 12851. Convention date, Sept. 13, 1941. [Class 97 (i) [Also in Group XL] In an optical system for forming in an image plane, such as a film 20, Fig. 1, a small area of light of variable intensity, and comprising a light source 10, a ribbon light valve 15 with at least one ribbon extending horizontally and vibrating vertically, a diaphragm 13 with an aperture 14 defining the top and bottom of the light beam between the light source and the light valve, a diaphragm 22 with an aperture 23 defining the sides of the light beam, a cylindrical rod lens 16 of small diameter is so positioned with its cylindrical axis horizontal and with its front focus close behind the ribbon that the front surface of the rod focusses near the rear surface a vertical punctual image of the diaphragm 13 and the rod lens focusses a vertical punctual image of the ribbon into the entrance pupil of an objective 18, 19 which forms on the film 20 a vertical image of the rear surface of the rod lens and a horizontal punctual image of the diaphragm 22. As shown, a cylindrical lens 17 is also positioned adjacent the diaphragm 22 to act as a field lens for this diaphragm; and the objective comprises a cylindrical lens 18 and -an ordinary high aperture objective 19. The ribbon light valve shown in Fig. 2 comprises magnets 25, polepieces 26, non-ferrous. spacers 27, and ribbons 28 in the gap between the polepieces. The inclined faces of the polepieces on the rear side of the valve are ground to form flat inclined seats 30. The planes of these seats intersect in the plane of the ribbons for correctly locating the cylindrical rod lens 29 which is held against the seats by springs, not shown. In a modification, Fig. 3, intended for experimental work, a cylindrical rod lens 36 is held at its ends in spring grippers 37, 38 adjustable by screws 39, 40. Specification 552,367, [Group XL], is referred to. |
