GB823131A - Improvements in prism lens systems - Google Patents

Abstract

823,131. Optical systems. KODAK Ltd. April 3, 1956 [March 31, 1955], No. 10099/56. Class 97(1) In an optical system comprising an objective in optical alignment with a variable prism anamorphoser consisting of at least two refracting prisms acting in opposite directions in the same plane and rota-; table in said plane to vary the anamorphotic effect a variable light deviation system is provided to compensate the duration of the optical axis produced by such rotation. The deviation system may also compensate the dispersion produced by the variable prism anamorphoser. As shown in Fig. 2 the anamorphoser prisms 31, 32 are rotatable before an objective 14 about axes 26 and 27 by mean of gearing 37, 39 to vary the magnification. A collimator comprising lenses 9,1, 92<SP>1</SP> is provided, the lens 91 being axially movable for focusing and the lens 92<SP>1</SP> being rotatable about an axis 25 coincident with' the centre of curvature of its front surface to provide, in addition, correction for the dispersion and axial deviation produced by the prisms 31 and 32, the rotation of the lens 92<SP>1</SP> being coupled to those of the prisms by gears 38 and 36. Alternatively the collimator may be fixed and the deviation and dispersion (of prism) of the prisms connected by a pair of wedges rotatable in opposite directions in plane perpendicular to the axis of the objective and placed between the latter and the prisms. In the form shown in Fig. 3 two pairs of prisms 61<SP>1</SP>, 62<SP>1</SP>, 61, 62, acting in perpendicular planes, are simultaneously adjusted to vary the magnification of sliding movement of a rack 47 engaging suitable gears 48, 48<SP>1</SP>. Correction of the resultant deviation of the axis is produced by a mirror 41 rotatable about an axis 43 and moved in synchronism with the prisms by means of a follower 45 engaging a cam surface 46<SP>1</SP> on a bar 46 attached to and sliding with the rack 47. The incident light is reflected first from a fixed mirror 40 on to the movable mirror 41 and thence to the prism system. Specification 823,129 is referred to.