GB436569A - Improvements in multiple objectives for three-colour projection - Google Patents

Abstract

436,569. Objectives for colour projection. VALENTIN, A., 11<bis>, Rue du Lunain, and BASSANI, L., 288, Rue de Vangirard, both in Paris. April 4, 1935, No. 10502. Convention date, April 12, 1934. [Class 97 (i)] A multiple objective for three-colour projection, particularly from kinematograph film having all the colour record images in a single normal image space, comprises a mount containing three separate objectives of which one is only capable of axial displacement for focusing, while each of the others, in addition to being axially movable, can also be displaced in any direction at right-angles to its axis to obtain proper registration of the projected images. The separate objectives 16, 17, 18 are carried in mounts 24, 30 within a barrel 15 which fits into the objective tube of an ordinary projector, the mounts being provided with lugs 23, 31 slidably mounted on rods 21, 22, 35, 36 extending parallel to the axis of the barrel. The rods 21, 22 are mounted in collars 19, 20 formed on the inner surface of the barrel and the lug 23 is internally threaded to receive a screw 26 which is prevented from moving axially by a shoulder 27 engaging in the end washer 28. The screw has a squared end 29 and can be rotated from outside the casing for focusing the lens 18. The rods 35, 36 carrying the mounts 30 for the lenses 16, 17, are mounted in rings 37, 38 the diameter of which is less than the internal diameter of the barrel 15, these rings having vertical slots 39 in which engage projections 40 carried by rings 41, 42 of the same diameter as the rings 37, 38. The rings 41, 42 have horizontal slots 43 engaged by projections 44 carried by the collars 19, 20. The mounts can thus be adjusted in any direction at right-angles to the lens axes, the adjustment of the rings 37, 38 relatively to the rings 41, 42 being effected by a rod 45 bearing in the end washers 28, 57 and passing through clearance apertures 46 in the rings 41, 42. The rings 37, 38 are formed with apertures 48 engaged by an eccentric part of the rod so that rotation of the rod causes displacement of the rings. The rings 41, 42, can similarly be displaced relatively to the casing by a rod 50, the rods 45, 50 having squared ends by which they can be rotated from outside the casing. The lenses 16, 17 are axially displaceable for focusing by screws 32 engaging the lugs 31. The rings 37 &c. are held between the collars 19, 20 and washers 28, 57, the latter being secured by nuts 59, 60. To enable the barrel 15 to be secured within the tube of the projector a member is provided which can be moved radially outwards from the barrel by means of an eccentrically mounted rod so as to press against the inner surface of the tube.