To produce on a screen an image of a diffraction grating pattern provided on a surface in which grating portions extending in one direction are represented bright and grating portions extending at right angles thereto are represented dark, the grating pattern is illuminated by a tubular lamp extending in the direction of the first mentioned grating portions through an autocollimator lens, the direct-reflected rays being intercepted by a lamp shield while the light diffracted by grating portions ...

A highly corrected compact optical system which has a large telephoto ratio, and which is particularly adapted for a photographic objective, is provided by a catadioptric system consisting of a solid refractive support which has a portion of smaller diameter projecting from its forward end and internal reflecting surfaces on its opposite end. An annular convergent reflecting surface on the rear end of the support reflects incoming light back through the support to a circular divergent reflecting...

Singlet lenses, and optical systems comprising a singlet lens and a stop, in which at least third-order distortions such as spherical aberration, coma, astigmatism and distortion are reduced by the use of glasses having radial, or axial, refractive index gradients.

A cathode structure, particularly a MK cathode, employs a wick mounted in a coupling member adjacent a supply of emission substance, preferably barium. The wick may be formed of a number of very thin tungsten wires which are snaked or braided together and covered with a cylindrical coating of, for example, molybdenum. The wick and the emission supply substance are mounted in a housing adjacent a heater element for indirect heating. A matrix of cathodes is provided by fixing coupling members havi...

An objective consisting of five lens members. The first two lens members are menisci curved towards the object, the first lens member having collective refractive power and the second lens member being composed of at least two separate lenses. The third and fourth lens members have a collective effect and consists of several individual lenses. The fifth lens member is a meniscus with dispersive refractive power, cemented from several separate lenses and curved towards the image. The invention co...

Unmodulated, collimated white light is angularly directed to a target reflecting surface which is deformable to represent a subject, and the subject-modulated light reflected from the target surface is directed to a viewing screen by a Schlieren optical system including a projection lens and a stop at the focal point of the lens. A first prism is located between the subject-bearing target surface and the lens to render the light reflected from the target surface orthogonal to the principal plane...

An accurate lens system for producing an extremely small image in a reduced scale, which is constructed as 6 components and 8 lenses and consists of first and second components of positive meniscus lenses, each component consisting of a single lens, third and fourth components of negative lenses, each component consisting of two lenses made integral into a unit lens, and fifth and sixth components of positive lenses, each component consisting of a single lens, all lenses being arranged in succes...

An optical system in which a plurality of light sources is used in conjunction with a spatial filter to modify at least some of the details of a projected image so as to increase or decrease the image contrast with respect to such details.

A wide angle biocular eyepiece comprising four or five spaced optical elements.

Apparatus for constructing holograms in which reflective or refractive materials are used to recover normally lost object radiation to thereby produce higher spatial frequencies in the reconstructed image, enlarge the effective numeric aperture at relatively long object-to-hologram distances, and improve image resolution. Image intensity is also improved.