Abstract: An optical transparency assembly suitable for use in applications where substantial pressure, temperature and humidity differentials between the air spaces on its opposite sides must be withstood, with one of its external surfaces maintaining a precise contour. One embodiment of the transparency assembly meets these requirements by including two separate transparent panels joined together at their peripheries with a narrow air space defined between them, with a unit being provided for conditioning the air in this narrow space such that it has a pressure, temperature and humidity substantially the same as that in the space adjacent the surface whose contour is to be maintained. Pressure, temperature and humidity gradients across one panel of the transparency assembly are minimized and that panel's contour is thereby precisely maintained.

Abstract: An optical transparency adapted to substantially attenuate electromagnetic pulses incident on it, yet transmit visible light with minimal distraction being caused by Fraunhofer diffraction. The transparency includes a transparent sheet and a laminated, electrically-conductive grid that defines a densely-packed array of apertures. Each aperture is a modified polygon having multiple curved sides, such that visible light from a remote point source of light is diffracted by the curved sides of each aperture over multiple, diverging, fan-like areas and minimal distraction to a person viewing through the transparency is thereby provided.

Abstract: A contoured transparency such as an aircraft windshield or canopy, and a method for making it, that provides reduced optical distortion for a pilot seating beneath it. The transparency is configured to have a tailored thickness gradient across its surface such that light passing obliquely through it and converging at a predetermined low distortion point is refracted in such a way the optical distortion is minimized. In one embodiment, the thickness gradient is selected such that light passing obliquely through it and converging on a single point follows a path after exiting the transparency that substantially parallels its path before entering the transparency. This eliminates angular deviation of a line of sight from that specific low distortion point. In another embodiment, the thickness gradient is selected such that the angle between the lines of sight of the pilot's two eyes to a remote target remains unchanged after passing through the transparency. This eliminates binocular deviation.

Abstract: A focusing reflector comprises a sheet of transparent material such as acrylic or the like formed to have a smooth-surfaced upper face and a lower face with a modified corner cube geometry. The modified corner cube geometry includes a plurality of multifaceted reflective elements arranged in a hexagonal close pack relationship with each element being defined by three planar facets forming a pyramid-shaped structure. Each element has two of its facets oriented mutually perpendicularly, and the third facet is oriented with respect to the perpendicular facets at a predetermined angle other than ninety degrees for redirection of light incident upon the upper sheet face toward a prescribed focal zone. The angular orientation of the third facet of each element is a function of the location of the element with respect to the position of the focal zone, together with the desired size and shape of the focal zone.

Abstract: A focusing device for concentrating radiation, such as sunlight, and producing a prescribed distribution of energy over a target surface. The principles of the device have both photovoltaic and photothermal applications, and can be embodied in either a lens or a mirror, having a plurality of discrete focusing surfaces for redirecting radiation onto a target surface. The angle for each of the respective focusing surfaces, relative to the direction of the radiation being received, is selected to redirect an increment of such radiation to a unique portion of the target surface, whereby a superposition of the radiation increments redirected by all of the focusing surfaces produces the prescribed distribution of energy on the target. In one embodiment, a plurality of focusing segments is provided each having a plurality of the focusing surfaces for irradiating the target surface with a prescribed energy distribution.