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: Cube-corner retroreflective article having improved divergence profiles. The three lateral reflecting faces of the cube-corner retroreflective elements are formed by three intersecting sets of parallel V-shaped grooves, and at least one of the sets includes, in a repeating pattern, at least two groove side angles that differ from one another. Thereby the array of cube-corner retroreflective elements is divided into repeating sub-arrays that each comprise a plurality of cube-corner retroreflective elements in a plurality of distinctive shapes that retroreflect incident light in distinctively shaped light patterns.

Abstract: A high-density rapid random - access retrieval apparatus for retrieving micrographic and data images stored on plural windowed discs. The apparatus is comprised of a disc/radial selection mechanism which moves axially of a cartridge containing a stack of closely spaced discs. Each disc has a clear window disposed on a radius thereof and a plurality of windows containing micrographic and/or data images disposed along other radil. When the disc/radial selection mechanism has moved to a selected disc, the radial component rotates the disc until the radius upon which the desired image is located is aligned with the clear windows in the other discs. The optical system includes lens and reflecting surfaces. At one end of the system is a projection means and at the other end lies its receiving means. Elements of the system are vertically adjustable so that the line of sight of the system is projected through any selected image bearing window.

Abstract: A lens of a transparent material including a structured surface on one side and a smooth surface on the opposite side. The structured surface includes a plurality of three-faceted prisms arranged side by side to form a plurality of ridges and grooves. Each prism has a reflective surface adjacent to a refractive surface and a riser adjacent to the refractive surface. The surfaces are angled with respect to one another so that incident light is transmitted through the lens, whereby the exiting rays may be predisposed to be perpendicular or non-perpendicular. Because of this the lens can be used to disperse, collimate, gather or concentrate the light. Thus, it may be utilized in a variety of ways, for example, in a light fixture, whereby high-angle incident light directed toward either the structured surface or the smooth surface, is transmitted through the lens and is directed in a desired fashion.

Abstract: A high-density rapid random-access retrieval apparatus for retrieving micrographic and data images stored on plural windowed discs. The apparatus is comprised of a disc/radial selection mechanism which moves axially on a cartridge containing a stack of closely spaced discs. Each disc has a clear window disposed on a radius thereof and a plurality of windows containing micrographic and/or data images disposed along other radii. When the disc/radial selection mechanism has moved to a selected disc, the radial component rotates the disc until the radius upon which the desired image is located is aligned with the clear windows in the other discs. The optical system includes lens and reflecting surfaces. At one end of the system is a projection means and at the other end lies its image receiving means. Elements of the system are vertically adjustable so that the line of sight of the system is projected through any selected image bearing window.