Abstract: A lighting apparatus has a lighting filament (3), a first lens (1) disposed at a fixed distance from the filament (3), divergent light from the filament falling directly on the first lens (1) which reduces but does not eliminate the divergence of the light in all directions about the optical axis upon passage of light through the first lens, and a sleeve (12) carrying a second lens (2) mounted for sliding movement relative to the box. The second lens (2) receives divergent light directly from the first lens (1) and reduces the divergence of the light upon passage of the light through the second lens, the focal length of the second lens being greater than 1 1/2 times the focal length of the first lens and the distance between the lenses being less than 1 1/2 times the focal length of the first lens. The illumination pattern is high-intensity but does not have a sharp contour so that it may be used in a surgical operating room.

Abstract: Two movable groups of lenses forming a variator are controlled by means of a computer and these groups are accordingly subjected not only to the necessary displacements of each group for the progressive variations of focal length but also to a complementary longitudinal displacement for applying to the objective-lens system a focal-length multiplier coefficient having a value chosen by the operator. The device in accordance with the invention comprises a control system associated with a computer and capable of subjecting the two movable groups of lenses to a complementary longitudinal displacement in order to apply a focal length multiplier coefficient to the objective-lens system, another function of the computer being to produce the desired variation of the iris and the complementary displacements of the focusing groups in respect of each focal length. The longest possible focal length can thus be chosen as a function either of the selected numerical aperture or of the field to be covered.

Abstract: The variable-focal-length objective for motion-picture cameras and especially color television cameras comprises two movable groups of lens elements placed between two stationary groups of lens elements and capable of displacement so as to produce a variation of the focal distance. In this objective, the two movable groups each take part in the total variation of magnification; each elementary magnification has a minimum and maximum absolute value during the variation, such that the ratio of maximum value to minimum value is higher than 1:1. However, only one of the two movable groups which does not pass through a magnification of unity performs both a magnification function and an additional focusing function. On the other hand, the other movable group which may pass through a position corresponding to a magnification of unity performs only a magnification function.

Abstract: These device and method for adjusting the value of the chromatism and distortion aberrations in an optical system, notably for color television cameras, by using a diascope from which a color image is injected into the optical system, comprises an assembly of at least four prismatic blades forming two optically parallel groups of variable thickness, each group comprising two such blades, the blades consisting of transparent materials having the same index of refraction and the same index of dispersion of the blades of the same group, but a different index of dispersion for each group, with control means for varying the thickness of each group while preserving a constant total thickness.

Abstract: An optical device comprising at least an optical element having a cut away area and which supports an inner mechanical structure accommodated in the cut away area, the whole being supported by an outer mechanical structure without obstruction in the optical path between the structures. The contact areas of the optical element with the structures comprise mechanical gripping and position means including deformable members for holding an unvaried centered position to the optical element for severe temperature and mechanical operating conditions.

Abstract: This lighting projector, notably for surgical theaters, comprises a plurality of elongated basic elements extending radially from a central casing outwards and disposed by pairs in relative alignment and a light source for each pair of elements, disposed adjacent one of the two elements involved, with a pair of frosted zones adjacent said source, and a reflection mirror and an optical system adapted to form an image of said source on the field to be illuminated after reflecting said image on said mirror.

Abstract: A lighting projector, notably for surgical theatres, comprising a central case enclosing light sources, and radial basic elements of tubular configuration provided with optical means for reflecting the light rays received from said sources towards the area to be illuminated, said means comprising notably a first mirror and a second mirror, the latter being disposed on the path of the light rays and capable of returning one portion thereof towards the area to be illuminated while allowing the other fraction to pass towards said first mirror located at the outer end of the element.