Abstract: A polarized component is obtained with a high conversion efficiency in a light guide which produces one of the polarized components by having it transmitted. The light from a light source is incident to a light guide which comprises a plurality of light guide layers and reflected by the end surface to an interface between the light guide layers. The polarized component transmitting through the end surface is rotated in its polarization plane by a wave length plate and reflected by a reflecting plate for reentrance to the light guide at the end surface of the light guide toward the interface. The reentering light mostly transmits through the interface because the polarization plane is rotated. A reflected light polarized component is returned to the wave length plate and the reflecting plate, and directed back to the interface again. The polarized component transmitting through the interface is similarly transmitted and reflected in the next interface.

Abstract: A plane light source apparatus having a lamp as light source and a light guide plate for directing and emitting the light from the lamp, wherein said light guide has a light incident surface opposed to said lamp and where the light from the lamp enters, a light emitting surface for emitting light from the lamp, and an opposed surface opposed to the light emitting surface, said light emitting surface or said opposed surface extends in the direction opposed to said light incident surface, has a plurality of convexoconcave portions formed to collect substantially light propagating in said light guide plate, and said connvexoconcave portions have a flat face formed at the bottom of the concave portion or at the top face of the convex portion.

Abstract: A polarized component is obtained with a high conversion efficiency in a light guide which produces one of the polarized components by having it transmitted. The light from a light source is incident to a light guide which comprises a plurality of light guide layers and reflected by the end surface to an interface between the light guide layers. The polarized component transmitting through the end surface is rotated in its polarization plane by a wave length plate and reflected by a reflecting plate for reentrance to the light guide at the end surface of the light guide toward the interface. The reentering light mostly transmits through the interface because the polarization plane is rotated. A reflected light polarized component is returned to the wave length plate and the reflecting plate, and directed back to the interface again. The polarized component transmitting through the interface is similarly transmitted and reflected in the next interface.

Abstract: A polarized component is obtained with a high conversion efficiency in a light guide which produces one of the polarized components by having it transmitted. The light from a light source is incident to a light guide which comprises a plurality of light guide layers and reflected by the end surface to an interface between the light guide layers. The polarized component transmitting through the end surface is rotated in its polarization plane by a wave length plate and reflected by a reflecting plate for reentrance to the light guide at the end surface of the light guide toward the interface. The reentering light mostly transmits through the interface because the polarization plane is rotated. A reflected light polarized component is returned to the wave length plate and the reflecting plate, and directed back to the interface again. The polarized component transmitting through the interface is similarly transmitted and reflected in the next interface.

Abstract: A reflection type display having a front light comprises a light guide plate having a light incident portion to which the lights are introduced, a planar surface arranged on the surface facing said first substrate and a prismatic surface arranged on the other surface, said prismatic surface comprising pseudo-planar surfaces which are formed at an angle of approximately 0.5 to 3.5 degrees with said planar surface and are raised greater as being distanced away from said light incident portion and slanted surfaces which are formed at an angle of approximately 40 to 60 degrees with said planar surface and are descended greater as being distanced away from said light incident portion, said pseudo-planar surfaces and said slanted surfaces are arranged alternately to form multiple prisms.

Abstract: The invention is intended to reduce the weight of the entire unit, make it compact and prevent the emitted light from being in dark and bright stripes in a light guide unit for a back light of a liquid crystal display device. Further, this invention allows a prism sheet having a larger apex angle to be used. To this end, the light guide unit comprises a plurality of light guide films laminated on the light guide member. The sloped surface which is opposite to the incident surface of the light guide unit is formed with grooves each having an inclination of an angle related to Brewster angle. A prism sheet is further disposed with the side having apexes oriented to the light guide unit to deflect the light emitted from the light guide unit.

Abstract: A polarized component is obtained with a high conversion efficiency in a light guide which produces one of the polarized components by having it transmitted. The light from a light source is incident to a light guide which comprises a plurality of light guide layers and reflected by the end surface to an interface between the light guide layers. The polarized component transmitting through the end surface is rotated in its polarization plane by a wave length plate and reflected by a reflecting plate for reentrance to the light guide at the end surface of the light guide toward the interface. The reentering light mostly transmits through the interface because the polarization plane is rotated. A reflected light polarized component is returned to the wave length plate and the reflecting plate, and directed back to the interface again. The polarized component transmitting through the interface is similarly transmitted and reflected in the next interface.

Abstract: Since a backlighting apparatus 1 for liquid crystal display is constituted such that a light guiding plate 2 and a frame 3 are molded together as a single unit provided with a deformation relaxation design, an attaching unit and parts, such as attaching feet and screws, for attaching the light guiding plate 2 to the frame 3 are not required, thereby making it possible to reduce the thickness and size of the backlighting apparatus 1 for liquid crystal display which has been restricted by the sizes of these parts.

Abstract: A back light device for a liquid crystal display is provided, which comprises diffusing prisms formed on the surface of the light guide plate, and the apical angle of the diffusing prism is set in the range of 65-85 degrees for a uniform and brighter illumination using the same light source.

Abstract: A flat lighting device designed to be free from accidental breakage of the leading-in wires for the luminous body comprised therein if they are subjected to vibration in use to consequently enhance the overall reliability of the flat lighting device. Such a flat lighting device comprises a panel-shaped transparent substrate, a light source holding unit fitted to an end face of the substrate and a tubular luminous body fitted to said light source holding unit and is characterized in that said light source holding unit is made of a conductive material and has a substantially U-shaped cross section such that it engages said end face at the open side thereof and that one of the leading-in wires of said luminous body is connected to said light source holding unit to form thereon a power feed section for the luminous body.

Abstract: A planar illuminating device, comprising a light-transmitting plate made of a transparent material and having opposite side edges and opposing front and rear faces, two sources of light each arranged adjacent to one of the side edges of the plate, a reflector arranged behind the plate rear face and reflecting rays of light from the plate to the front face of the plate, a light diffuser arranged in front of the plate and diffusing rays of light from the plate. The device comprises a reflecting finish applied directly to the rear face of the plate. A reflecting surface of the reflecting finish faces substantially in the direction of the front face of the plate. The reflectance of part of the reflecting finish depends on the distance of that part from either of the two sources of light. The device further comprises parallel prismatic cuts along the front face of the plate. The longitudinal axes of the prismatic cuts are substantially parallel to rays of light passing from the sources of light through the plate.

Abstract: A circuit system for preventing a measuring device such as an engine speed measuring device or the like from being erroneously operated includes as essential components a filter circuit, a Schmitt trigger circuit, an oscillating circuit, a counting circuit, a pulse monitoring circuit and an adding circuit. A combination of the filter circuit and the Schmitt trigger circuit serve to properly shape a wave form of each of a series of pulse-shaped sensor detection signals. The oscillating circuit generates a series of pulses each having a reference frequency. The pulse monitoring circuit monitors a wave-form shaping output pulse by counting the number of a series of output pulses each having a reference frequency for a predetermined period of time with the edge of the wave-form shaping output pulse as a trigger.