Abstract: A light guide is comprised of a laser light source for providing a light beam along a central axis, an optical system for collimating and focusing the beam at infinity, a virtually cylindrical convex lens fixed in a position to intercept the focused beam wherein the angle between the centreline of the beam and the optical surface at its exit point from the lens is an oblique angle whereby the beam is spread radially toward a target, and thereby form a line of light on the target, and whereby the target surface can be located at various distances from the lens while the width of the beam impinging thereon is maintained along a straight line with constant width on a target surface at an angle to the plane thereof.

Abstract: A diffuser for backlighting a display panel consists of a shell having a flat surface for positioning against the backside of the panel. The shell has a cavity with two sections. A reflection cavity section extending into the shell from the flat surface has highly reflective walls one of which opposite the mouth of the cavity defines a ramp. An illumination cavity section extending into the shell intercepts the reflection cavity section at a boundary near the foot of the ramp. When light propagates from the illumination cavity section into the reflection cavity section, the walls of the latter cavity section distribute that light by reflection and the ramp redirects that light to the mouth of the reflection cavity section from which the light propagates to the display panel as a uniform diffuse emanation.