GB601573A - Improvements in or relating to optical projection devices - Google Patents

Abstract

601,573. Optical-projection apparatus. EYME, A. E. Dec. 17, 1945, No. 34161.. Convention date, Dec. 22, 1944. [Classes 97 (i) and 98 (i)] The apparatus comprises as shown, a projection device 2, the optical axis of which is substantially parallel to a screen 1 on to which is obliquely projected after reflection at 12, the image of a transparent picture 3. The picture is disposed in a plane, which is optically conjugated with the plane of the screen 1 with respect to the object glass 7 and carries an image, which has been anamorphosed to correct for distortion due to oblique projection. Such an anamorphosed image may be obtained by photographing a normal negative, the normal negative and the negative to carry an anamorphosed image respectively occupying the positions of the screen 1 and the transparent picture 3 during projection. The Specification as open to inspection under Sect. 91 comprises also an embodiment as described above, but without the reflector 12; it also refers to the projection of a distorted picture which is disposed orthogonally to the optical axis of the object glass 7, the sharpness of image being provided by a suitable diaphragmation of the object glass. A cylindrical lens, (Fig. 5, Cancelled), having different magnifying power at different points of its surface is disclosed for use in the oblique projection of an undistorted transparency, this lens being between the transparency and object glass and the parts 16, 17 thereof being concave and convex respectively. Such a picture may also be imaged on a ground glass screen, which image is then projected through an object glass on to a screen 1, the screen 1 and the ground glass being optically conjugated with reference to the object glass. This subjectmatter does not appear in the Specification as accepted.