Abstract: A reflector has a plurality of Fresnel-type structures, wherein at least some of said Fresnel-type structures have a plurality of active faces, for reflecting light in a plurality of directions.

Abstract: A high aspect ratio light fixture has an optical window with a light extraction film therein. The light extraction film has a plurality of linear prisms facing the interior of the light fixture. In one embodiment of the invention the prisms are triangular in shape while in another they are four sided.

Abstract: A thin, flexible film made of a transparent polymeric material including a structured surface and an opposite smooth surface, wherein light striking either surface, within certain angular ranges, is totally internally reflected. The structured surface includes a linear array of miniature substantially right angled isosceles prisms arranged side-by-side to form a plurality of peaks and grooves. In addition, the perpendicular sides of the prisms make an angle of approximately 45.degree. with the smooth surface, and when the film is curled the smooth surface lies in a smooth continuous arcuate curve without materially affecting the performance of the film. Because of the film's flexibility and its ability to totally internally reflect light, it may be utilized in a variety of ways, for example, as a collector of solar energy or as a light conduit. The performance of the film may be manipulated to permit controlled light leakage.

Abstract: In the present invention a wide angle safety lens has two major surfaces, each of which is a structured surface. The first major surface has a plurality of parallel linear prisms forming a Fresnel lens that acts like a cylindrical lens having a first negative focal length. The second major surface has a plurality of parallel linear prisms running perpendicular to the prisms of the first major surface and forming a Fresnel lens that acts like a cylindrical lens having a second negative focal length.

Abstract: The present invention provides a retroreflective material which has improved retroreflectivity at high angles of incidence. The retroreflective material comprises a transparent surface layer and an array of reflecting elements, each of the reflecting elements including a rectangular base having a length L, two tetragonal faces nearly perpendicular to each other and having a line of intersection of length Y, the length Y being less than said length L, a triangular face nearly perpendicular to the tetragonal faces; and a non-perpendicular triangular face forming an angle alpha with the plane perpendicular to the base, the angle alpha being preferably about sin.sup.-1 (0.25/n) to sin.sup.-1 (l/n), and more preferably about sin.sup.-1 (0.35/n) to sin.sup.-1 (0.

Abstract: A hollow, tubular light conduit including a wall of a transparent polymeric material, and the wall having a structured surface and an opposite, smooth, glossy surface, and at least a portion of the cross-section of the wall lying in a smooth arcuate curve, wherein light striking the inner surface, within an acceptable angular range, is contained by total internal reflection. The structured surface includes a linear array of substantially right angled isosceles prisms arranged side-by-side to form grooves. In addition, the perpendicular sides of the prisms make an angle of approximately 45.degree. with the tangent to the smooth surface. Because of the flexibility of the light conduit and its ability to totally internally reflect light, a manipulated light conduit may be utilized in a variety of ways, for example, as a light fixture whereby some of the light directed into the light conduit is emitted from the light conduit for illumination or for use as a secondary light source.

Abstract: A tanning blanket for reflecting a large portion of the solar radiation which is otherwise scattered in directions away from the person using the blanket, towards the flanks of the person, the blanket having a plurality of incremental reflectors in a Fresnel pattern on a flexible substrate, which reflectors reflect incident solar radiation toward the person and distribute the reflected radiation across the flanks of the person.

Abstract: A skivable billet having improved uniform heat absorptive ability in which layers of enhanced optical density comprise water soluble polyazo direct dyes such as Formanil Black G and finely divided silica.