Abstract: A surface light source of side light type comprises a light scattering guide plate, primary light source, reflection sheet, and prism sheet acting as a light control member. An emission surface of the light guide plate provides a light control surface (arrow C). This light control surface has a great number of fine projections running approximately perpendicular or inclined at a small angle to an incidence surface. A pair of slopes are formed on each of the projections. A prism sheet has a light control surface opposing the light control plate (arrow B). The projections on the prism sheet extend approximately parallel to the incidence surface. An inclination angle of a slope may be selected so that an emission light from the light guide plate is received at a small incidence angle. An inclination angle of a slope may be selected so that an emission light from the prism sheet to the frontal direction can be obtained. A back surface of the light guide plate may provide a light control surface.

Abstract: A surface light source device of side light type has a scattering guide plate, a primary light source, a reflection sheet and a prism sheet. An emission surface of the guide plate provides a light control surface. The light control surface has many fine projections approximately perpendicular to an incidence surface or inclined by a small angle with respect to the incidence surface. In each of the projections, dullness varying in accordance with position on the emission surface is given to a slope-couple including a pair of slopes produce a uniform emitting intensity from the emission surface. A back surface of the guide plate may provide a light control surface so that dullness varying in accordance with position is given to slope-couples.

Abstract: A liquid crystal display includes a LCD panel and a surface light source device of side light type to illuminate the panel. The surface light source device comprises a guide plate having an emission face, a back face and an incidence face, a primary light source to supply light through the incidence face, and a reflection member disposed along the back face. The reflection member has an inner reflection face including a plurality of fine regions to control angular extension of illumination output. The fine regions are provided with scattering property which is different from that of the rest region. In cases where emission promoting power (scattering power) of the emission face falls according to distance from the incidence face, the reflection face of the reflection member is provided with scattering power which varies so as to tend to compensate said falling of emission promoting power. Fine regions are arranged in corner portions located at both ends of the incidence face to avoid short of emission.

Abstract: A surface light source device of side light type is provided with guide plate, a primary light source, a reflection sheet and a prism sheet. The back surface of the guide plate provides a light control surface (arrows D to F). This light control surface has a great number of projections running generally at right angles to an incidence end surface. Each projection includes a pair of slopes. Inclination angles of the slopes of the pair with respect to a normal to a general plane of the guide plate are equal to each other on a generally central portion of an emission surface, while inclination angles of respective inner slopes become larger gradually than those of respective outer slopes toward areas near both side portions, as viewed from an incidence end surface. Length between two side edges of the guide plate may be larger than length thereof along the running direction of the projections, as viewed from the incidence end surface.

Abstract: Local irregularities in luminance are removed from a surface light source device of side light type 20 applied to a liquid crystal display or the like. In assembly, a reflection sheet 4 and a primary light source 23 are mounted on a light guide plate 2, and these components are housed at a predetermined position in a frame 21. The primary light source 23 has a fluorescent lamp 25 and a reflector 26, and supplied illumination light to an end surface (an incidence surface) 2A of the light guide plate 2. The reflector 26 presses the reflection sheet 4 against the light guide plate 2 and supports the reflection sheet. A support member 24 has a claw 24C engageable with a claw 21C of the frame 21. A light absorbable layer 27 is formed on an end portion of the reflection sheet 4.

Abstract: A surface light source device of side light type is provided with a guide plate, a primary light source, a reflection sheet, and a prism sheet providing a light control member. An emission surface of the guide plate provides a light control surface (arrow C). The light control surface has a large number of minute projections each of which extends generally orthogonal or slightly obliquely to an incidence surface. Each projection has a pair of slopes. A surface of a light control member (prism sheet) is opposite with the guide plate to provide another light control surface (arrow D). Projections on the light control member extend generally in parallel with the incidence surface of the guide plate and each have first and second slopes which are relatively remote from and relatively near to the incidence surface, respectively. Inclination angle .beta.2 of the second slope (as defined with respect to a normal erected on a general surface of the guide plate) is small compared with inclination angle .beta.

Abstract: A surface light source device of side light type includes a primary light source, a reflection sheet, a light scattering guide plate, and a prism sheet. The primary light source comprises a fluorescent lamp and a reflector to supply illumination light toward an incidence surface of the light scattering guide plate. The light scattering guide plate has an emission surface and a back surface, with the prism sheet being disposed along the emission surface. On the emission surface and/or the back surface, a great number of grooves running generally perpendicular to the incidence surface within a range of distance W1 and/or W2 from an upper edge EU and/or a lower edge EL. These grooves provide a corrugate shape in a cross section parallel to the incidence surface. Depth of corrugate shape gradually becomes shallower as getting away from the incidence surface.

Abstract: A pyroelectric infrared detector used in the intrusion detection system, the detector including a housing having an opening, at least two infrared transmissive pyroelectric layers spaced to be mutually free from thermal influence; and a plurality of electrodes formed on the surfaces of each of the pyroelectric layer, the electrodes electrically connected to each other.

Abstract: A passive-type moving object detection system is disclosed. The system includes an infrared detector, infrared sensors mounted on the infrared detector, a detection field including two columns of detection regions for monitoring a human intruder and two rows of detection regions for detecting a non-human intruder. The columns have a height corresponding to a human height, and an optical system is located between the infrared detector and the detection field. The infrared sensors have infrared accepting areas that include first and second sections. The first section optically corresponds to the columns and the second section optically corresponds to the rows. Each sensor receives infrared radiation from a moving object passing through the detection regions. The detector includes an arithmetic circuit that subtracts the peak values of signals generated by the detector and a decision circuit to compare the result with a reference level.