Abstract: A photointerrupter includes a base, a light emitting element, a light receiving element, a light-transmissive detector resin member covering the light receiving element, a light-transmissive emitter resin member covering the light emitting element, and a light shield layer covering the detector resin member and the emitter resin member. The emitter resin member is spaced apart from the detector resin member with an intervening clearance between them. The detector resin member includes a light incidence surface exposed from the light shield layer, and the emitter resin member includes a light output surface exposed from the light shield layer. The light incidence surface and the light output surface are arranged to face the clearance between the two resin members.

Abstract: A linear light source device illuminates a document properly, and an image reading device includes such a light source device. The light source device includes a light source and a light-guiding member. The light-guiding member introduces the light emitted from the light source from one end portion in x-direction, cause the light to travel in x-direction, and emits the light from a light exit portion at one end in z-direction, which is orthogonal to x-direction. The light-guiding member includes, at the other end in z-direction, a light-reflecting portion that reflects light to the light exit portion. One end face of the light-guiding member in y-direction, which is orthogonal to x- and z-directions, is inclined so as to become closer to the other end face in y-direction with decreasing distance from the light exit portion in z-direction. This allows light to easily travel to the light-reflecting portion.

Abstract: A photointerrupter includes a base, a light emitting element, a light receiving element, a light-transmissive detector resin member covering the light receiving element, a light-transmissive emitter resin member covering the light emitting element, and a light shield layer covering the detector resin member and the emitter resin member. The emitter resin member is spaced apart from the detector resin member with an intervening clearance between them. The detector resin member includes a light incidence surface exposed from the light shield layer, and the emitter resin member includes a light output surface exposed from the light shield layer. The light incidence surface and the light output surface are arranged to face the clearance between the two resin members.

Abstract: A linear light source device illuminates a document properly, and an image reading device includes such a light source device. The light source device includes a light source and a light-guiding member. The light-guiding member introduces the light emitted from the light source from one end portion in x-direction, cause the light to travel in x-direction, and emits the light from a light exit portion at one end in z-direction, which is orthogonal to x-direction. The light-guiding member includes, at the other end in z-direction, a light-reflecting portion that reflects light to the light exit portion. One end face of the light-guiding member in y-direction, which is orthogonal to x- and z-directions, is inclined so as to become closer to the other end face in y-direction with decreasing distance from the light exit portion in z-direction. This allows light to easily travel to the light-reflecting portion.