Improved backlighting apparatus evenly illuminates positive and negative LCDs under all ambient lighting conditions. Incandescent lamps (301-304) provide light for distribution by a light pipe (101). The bottom of the light pipe (101) is selectively painted white to reflect light to the top of the light pipe (101) while the unpainted areas reflect light internal to the light pipe (101), controlling hot and dim spots. The corners of the light pipe (101) near the lamps (301-304) are dual angled to...

At least part of a reflector surface covering a rod-shaped light source is a continuous body having such a shape that in a plane perpendicular to the central axis of the rod-shaped light source, a ray emitted from a light emitting point on the surface of the rod-shaped light source in the tangential direction going away from a light conducting plate is reflected back to the vicinity of the light emitting point. According to another aspect, at least part of a reflector surface covering a rod-shap...

In a backlighting device for use with display panels that comprises a light conducting plate made of a light-transmissive material, one of the major faces of said light conducting plate being provided with a light diffusing capability and covered with a specular or light diffusing/reflecting plate, and a linear light source provided in proximity to the end portion of at least one side of said light conducting plate, the improvement wherein at least one sheet that is made of a light-transmissive ...

A backlighting device for use with display panels has a plurality of light diffusing elements formed in dots or stripes on one of the two major faces of a light conducting plate that is made of a light-transmissive material. The device also has a linear light source provided in proximity to the end portion of at least one side of the light conducting plate. In the device, at least one sheet that is made of a light-transmissive material and which has a multiple of prisms or raised structures havi...

A backlighting keyboard includes a light guide board with multiple fastening members formed at an upper surface, multiple light refracting areas formed at a bottom surface, multiple openings defined through the light guide board, and multiple illuminants respectively received in the openings. A membrane printed circuit board on the light guide board has multiple nodes respectively aligned with the fastening members, and multiple first holes defined through the membrane printed circuit board. A r...

To achieve a backlighting device having excellent light utilization, there is provided an edge lighting-type backlight having a light guiding member, a high-refractive-index layer formed thereon and having a higher refractive index than the light guiding member, and a scattering layer formed on the high-refractive-index layer. Light from a light source disposed facing the edge of the light guiding member enters the high-refractive-index layer through the light guiding member, and effectively sca...

A backlighting device for display panels operating on the edge lighting method that comprises a light conducting plate made of a light-transmissive material, a layer of light-diffusing material that partly covers one major surface of the light conducting plate, and a light diffusing/reflecting plate that covers the thus covered area of the light conducting plate. The light conducting plate is provided on its exit face with a film that is coarser grained on the exit face than on the entrance face...

A backlighting device includes a light guide plate having a first side and a second side opposite to the first side, and a point light source to generate light incident on the first side of the light guide plate. The light guide plate has a plurality of longitudinal diffraction microstructures which are arranged and oriented according to the location of the point light source. The microstructures are varied gradually at least in size, position, density, or shape relative to the location of the p...

Disclosed is a lightguide in the form of a plate (1), a first surface of which is provided with first straight parallel grooves (8) (diffusing the light circulating in the guide). The inventive lightguide is characterized by the fact that it is provided with second straight parallel grooves (9) (diffusing the light circulating in the guide) which extend in an oblique direction, particularly in an orthogonal direction, relative to the first grooves such that the guide diffuses in a uniform manner...

The proposed device uses a plastic of any color with a cavity introduced in it and preferably with a polished inner surface, instead of a reflector or a light guide, to utilize increased reflection with grazing incidence (large angle of incidence versus the normal to the surface). The light from a light source is transported to the symbol by reflection in this cavity and on the inner surface. The light source is preferably of a flat structure.