U.S. Philips Corporation

Telecommunications Radioelectriques Et Telephoniques

Jean-Claude Perrin

Joel Rollin

Fernand R Loy

The bifocal optical system is formed in the long focal length mode by an objective having fixed lenses L1, L2, L3, L4 to which, for obtaining the short focal length, a group of movable lenses L5, L6, L7, L8 is added. The lenses L5, L6, L7 and L8 are accommodated in a holder (MB) which is rotatable around an axis YY' which extends parallel to the optical axis XX', thereby enabling very wide tolerances in the positioning of the movable holder.

Bifocal optical system

This varifocal optical system is electro-mechanically controlled to vary focal distance, temperature correction focussing and finite distance focussing. It is constituted by four single lenses (L1, L2, L3 and L4) two of which (L2, L3) are movable and are axially translated to vary the magnification, while only one (L3) of these two lenses is adapted for temperature correction focussing and finite distance focussing. It is also consituted by electro-mechanical member (EMM) which are especially adapted to control the movements of the two movable lenses (L2, L3) in a discrete manner.

Varifocal optical system and associated electro-mechanical control

Device used in aviation for in-flight reception of images corrects distortion resulting from the observation of a field of view through a wall (1) which is transparent in a given spectral band and whose shape distorts the image of the scene formed on a receiver (4). An optical system arranged between the receiver and the wall performs an anamorphotic function in one direction and a deviation function in another direction perpendicular thereto. The deviation function is realized by a single prism formed by two parts (5,6) cemented to one another and which have different refractive indices so as to form an achromatic assembly. The anamorphotic function is obtained by a slight change of the focal length of the receiver in conjunction with the elongation of lines formed by the prism in the direction of the deviation function.

Device for correcting the total distortion caused by the shape of a

Device for correcting the differential distortion resulting from simultaneous observation of a field of view at two distinct locations through a shield transparent in a given spectral band, which shield has a shape generating the distortion when a receiver which is sensitive in the spectral band is arranged at each of the locations. The correction is effected by an optical system arranged between the shield and one or the other receiver and comprising an anamorphic assembly (11, 12) producing an anamorphosis in a first direction associated with an element (13) introducing a curvature in a second direction, while the distortion produced by this system has a direction opposite to the differential distortion.

Device for correcting distortion

A sight comprises an image carrier (D) presenting an exit aperture (P3) and forming, from an observed image (I), an intermediate image (I') at the focus (F) of an ocular comprised of a spherical mirror (M) with the same optical axis (XX') as that of the image carrier (D), with a holographic beam deflection element (H) being placed at the focus (F) of the spherical mirror (M). In accordance with the invention, the intermediate image (I') is formed on the focal surface (S) of the ocular, and the holographic beam deflection element (H) is disposed on a support resting on the focal surface (S) and, in association with the spherical mirror (M), conjugates stigmatically the exit aperture (P3) of the image carrier (D) with the exit aperture (P1) of the sight.

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Vanves, France

Jean-Claude Perrin