Abstract: An optical instrument for indirectly observing an object includes a first lens system for producing a first image of the object, and an adjustable second lens system for producing a second image of the object. The second lens system is continuously adjustable between a first position wherein the second image has maximum magnification and/or a minimum area of view, and a second position wherein the second image is of a minimum magnification and/or a maximum area of view. In one aspect of the invention, the second lens system is a zoom lens system having two substantially fixed conjugate planes. In another aspect of the invention, the instrument defines a folded optical path through the lens systems which includes a generally U-shaped portion so as, in use, to reduce the separation of the observer and the observed object.

Abstract: A panoramic imaging system for projecting a 360 degree cylindrical field of view onto a two-dimensional annular format has a panoramic imaging block with a concentric axis of symmetry, two refractive surfaces and two reflective surfaces. The first reflective surface is a concave conicoid of revolution with the conic constant in the range from -0.6 to +2.0. In an embodiment of the invention, the second refractive surface (the last in the path of rays) is flat, while the first reflective surface, the second reflective surface and the first refractive surface are all spherical.

Abstract: A photolithographic projection optical system comprising: a source of exposure energy for generating a beam of energy; an optical element located in the path of the beam for receiving the beam of energy and passing the beam therethrough; a refractive lens assembly located in the path of the portion of the beam for receiving and transmitting the beam of energy, the refractive lens assembly comprising at least one meniscus lens, a plano-convex lens, and an air gap disposed between the meniscus lens and the plano-convex lens; a reticle element located in the path of the portion of the beam, the reticle element having a uniform thickness and being positioned for permitting the beam to pass through the thickness and through the lens assembly to the optical element. Alternatively, the air gap of the refractive lens assembly can be replaced with a glass layer having an index of refraction that is lower than both the meniscus lens and the plano-convex lens.

Abstract: A new type of lens is described. The lens has the appearance of a prism with a relatively sharp radius at the apex. This lens finds an application in expanding a laser beam in one direction only.