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: There is provided a surface light source device of side light type, which is not reduced in efficiency of illumination light utilization, even if the surface light source device is subjected to fringing such as to trim a luminant portion. For instance, a light shielding layer formed by coating black ink 21A, which absorbs illumination light, by means of printing is provided on a protection sheet 21 arranged as the outermost emission-side additional sheet. The light shielding layer absorbs and shields illumination light L1 tending to be transmitted through a peripheral edge portion of the protection sheet 12, and as a result, provides fringing. A reflective surface is formed by applying a silver tape 21B or the like to a surface facing the light guide plate 6. Since illumination light reflected by the silver tape 21B is used again inside the light guide plate 6, it is possible to avoid a reduction in efficiency of light utilization.

Abstract: In a surface light source device of side light type and a display employing the same, illumination light of high grade is allowed to emit by reducing irregularities in luminance caused along a muntin of a support member to support components such as a light guide plate 2 and a reflection sheet 21. A light quantity correction surface 21A is formed between the reflection member 21 and a support member 11. Otherwise, a member providing the light quantity correction surface is arranged on the rear of the support member. A quantity of illumination light in a portion of a muntin 11B of the support member 11 is made approximately equal to that in a portion of an aperture 11C, and the irregularities in luminance caused correspondingly to the muntin are reduced. The light quantity correction surface may be provided by a surface of the muntin itself or ink coated on the muntin by means of printing.