A light source in which a lamp aperture is arranged to illuminate a large panel provided with a reflective surface by having light rays from the aperture pass through a trough wherein such rays are changed so they are all substantially at angles greater than the critical angle necessary for total internal reflection. Light reflected from the panel is emitted through a window with the aid of light scatterers.
A flat lighting device (8; 32) having an aperture fluorescent lamp (33), an optical system (10; 34) and an optical conductor plate (11; 35) is provided. The optical system (10: 34) specifically influences the light distribution of the light to be coupled into the optical conductor plate in such a way that seen in a cross-sectional plane of the tubular discharge vessel of the lamp, the light distribution has at least one maximum at an angular spacing .beta., measured from the optical axis (A), the angular spacing .beta. fulfilling the following relationship: ##EQU1## L being the longitudinal extent of the optical conductor plate in the direction of the optical axis (A) and d being its thickness.
An improved backlighting system for electronic displays that require such backlighting is disclosed. The system comprises a fluorescent lamp with improved visible light generating means and a reflector means for channeling the light generated by the lamp into the electronic display. In particular, the lamp comprises, in a preferred embodiment, a cylindrical glass housing, sealed at both ends and containing a plasma which can be excited to generate short wavelength light. A strip of phosphorescent material is placed along the inside surface of the tube, the strip being relatively restricted in width, its width being partially determined by the thickness of the electronic display. A reflector surrounds the lamp and helps drive the light the lamp generates into the phosphor. The lamp is also comprised of a glass transparent to the frequencies of light generated by the plasma. By limiting the width of the florescent area to a strip, light efficiency (the ratio of light out of the display to the electrical power into the lamp) increases and power consumption is also reduced. Additionally, the incorporation of one of several types of light concentrators between the lamp and light guide can improve the light efficiency still further.
An illuminating device has a bar-shaped light, a light conductor plate and a U-shaped clamping part having two legs. The clamping part extends along the bar-shaped light and connects the light with the light conductor plate so that the clamping part embraces the light and a neighboring edge region of the light conductor plate in a U-shaped manner and the legs are elastically fixed on the light conductor plate.
A back lighting device which comprises a light conducting plate made of a light-transmissive material, a linear light source provided in proximity to the end portion of at least one side of the light conducting plate, a reflecting plate or film that covers the linear light source and which consists, in order from the light source side, of a specular reflecting plate or film, an air layer and a light diffusing/reflecting plate or film in superposition. One surface of the light conducting plate is provided with a light diffusing capability and covered with a specular or light diffusing/reflecting plate. Thereby, it is possible to provide a back lighting device that has a high efficiency of power to luminance conversion and which hence is capable of achieving high luminance.
The present invention relates to a flat parallel light source using the principle of the mirror reflection and diffuse reflection, which comprises a light source, a diffuse reflective chamber with high reflectance walls, a light coupler, a small hole array at the top surface of said diffuse reflective chamber, a mirror reflective cone array on the small hole array, and a convex lens array on said cone array. The light generated by the light pass through the light coupler into the diffuse reflective chamber, and then pass through the small hole array, mirror reflective cone array, and lens array to form parallel light. The flat parallel light source can generate a high intensity parallel light with excellent parallelism or a given scattering angle parallel light. It can be used for backlighting for all kinds of LCDs, and other equipment where parallel light is needed. It can also be used in LCDs to increase the brightness of the display image and reduce power consumption.
