A light scattering and guiding light source device which is capable of providing a uniform illumination light, simple structure and low cost. A wedge-shaped light scattering guide has an incident surface for introducing light rays from a fluorescent lamp. The directions of the rays are changed by scattering. The rays propagate through the body while reflected repeatedly. Parts of the rays go outwards at plural reflective points. The angle of reflection increases successively, thus increasing the possibility that the light exits from the exit surface. This effect cancels another effect that portions close to the light source shines strongly. Both effects are balanced to make uniform the brightness over the exit surface. Reflective sheets are disposed along the inclined surface and around the fluorescent lamp to keep the brightness high. A prismatic exit direction modifier giving on the light exit surface is employed to modify the light exit direction characteristic. The light source device is mounted on a liquid crystal display as a backlight source to provide an improved display quality.
This application is a continuation of application Ser. No. 08/403,880, filed Mar. 21, 1995, now abandoned, which is a 371 of PCT/JP94/01201 filed Jul. 21, 1994.
A light pipe has an upper surface, a lower surface, incidence side surfaces, and a light output device in one of the upper and lower surfaces so that light incident on each of the incidence side surfaces is made to exit from the other of the upper and lower surfaces through the light output devices. The light output device is constituted by a repetitive structure of irregularities having ridgelines along the incidence side surfaces, each of the irregularities having a pair of transmission light reflection surfaces which face the incidence side surfaces respectively, the transmission light reflection surfaces are inclined in directions opposite to each other, and having a pair of gentle slopes which are disposed between the pair of transmission light reflection surfaces, each of the gentle slopes is inclined in a direction opposite to the inclination direction of adjacent one of the transmission light reflection surfaces.
A flexible light emitting sheet is curved along a curved liquid crystal screen constituting a meter display, and comprises one of a single sheet of a flexible transparent resin with a system of monoxide silicon particles mixed therein, an electroluminescent substance relatively high of brightness, and a flexible transparent resin sheet and a set of light emitting diodes arranged thereon in a plane conforming manner.
A display device is described in which a fiber optic plate provided with light scattering particles is used for effective front lighting of a display, for example, a liquid crystal cell. The fiber optic plate is lighted from the side.
A communication system that allows two-way communication is provided with the use of a sheet-type optical conductor capable of providing a favorable level of light-extraction efficiency and uniformly distributed optical output power. The sheet conductor includes a sheet-type optical medium containing particles for reflecting light, and propagates the optical signal injected from one edge of the medium to the other having an optical receiver by scattering the optical signal by means of the particles, which is designed such that the value of .PHI.NpL.sub.GK.sub.C is less than or equal to 0.9, where .PHI. is the scattering cross-sectional area of the particles, L.sub.G is the length of the optical medium in the direction in which the light is propagated, Np is the density of the particles, and K.sub.C is a correction coefficient.
An optical illumination system is comprised of: (a) a light source means having a reflective emitting surface and an intrinsic luminance (brightness), (b) a light transmitting means; (c) a light reflecting means to reflect and recycle a portion of the light emitted by the light source means back to the light source means; and (d) a light extracting means to extract a portion of the light from the light transmitting means and direct the light to the output of the illumination system. The resulting illumination system achieves an enhanced output luminance. Under certain conditions, it is possible to achieve an output luminance that is greater than the intrinsic luminance of the bare light source.
