Other

Enplas Corporation

Yasuhiro Koike

Kayoko Masaki

Hiromi Sasako

Kayoko Watai

Kazumasa Ohsumi

An improved surface light source device applicable to back lighting of a liquid display. In the surface light source device, a plate-shaped optical block ( ) is disposed along an emitting surface of a plate-shaped optical member ( ), to which illumination light is to be supplied from a primary light source ( ), and has on at least one of its outer and inner sides a directivity modifying surface for modifying directivity of illumination light emitted from the emitting surface. Directivity modifying surface occupies at least part of the whole area of the optical block except a predetermined range (AR ) from a position aligning to the incidence surface of the plate-shaped optical member ( ). The optical block ( ) and the plate-shaped optical member ( ) may be held in a unitary form by a holding mechanism formed integrally with the optical block ( ) and/or the plate-shaped optical member ( ). One end of a reflection member about the primary light source ( ) may be pinched between the optical block ( ) and the plate-shaped optical member ( ).

Surface light source device

A light regulator and a surface light source device employing the light regulator. For liquid-crystal display applications, the surface light source device can effectively prevent degradation in the quality of the emitted light and can reliably provide the required directivity correction. The light regulator is formed by laminatedly arranging a light scattering surface between first and second sheet-like members. The two sheet-like members mutually differ in shape, material and refractive index. Scattering means arranged between the first and second sheet-like members prevents Newton's rings due to spaces between the two sheet-like members from occurring. A light diffusion sheet may be disposed between the first and second sheet-like members.

Light regulator and surface light source device

In a surface light source device of side light type, occurrence of irregularities in luminance is prevented in the vicinity of an incidence surface 10 of a light guide plate 1. A light source element 2 is disposed on a lateral side of the light guide plate 1 and the light introduced into the light guide plate 1 through the incidence surface 10 is emitted through an emission surface 11. The light comes outside after undergoing the action of an additional element 3 (such as a priority traveling direction correcting action) and is applied to, for example, back lighting in a liquid crystal display. A reflection sheet such as a silver foil is disposed along a rear surface 12. The rear surface 12 is treated in various manners in order to reflect the light toward the emission surface 11. Another reflection sheet 20 is disposed as a reflector surrounding the light source element 2 from the back side. A case 4 partially projects inward along the incidence surface 10 to form light shielding walls 8, 9. The shielding walls 8, 9 are adapted to prevent light emitted from the light source element 2 from intruding through gaps G1 to G4 between the elements, or through an end surface of an end edge portion 3a of the additional element.

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Kawaguchi, Japan

Kayoko Masaki