Abstract: An apparatus includes a two-sided prism sheet, and an optical path conversion unit with linear prisms. Each apex angle of the prisms increases the closer the linear prism is formed to the center in the light guide direction, and when a pair of inclined surfaces of each of the prisms has a first inclined surface and a second inclined surface, an inclination angle of the second inclined surface is larger than the one of the first inclined surface. Among the prisms, inclination angles e1 and e2 of a pair of inclined surfaces of a linear prism formed closest to the center and an inclination angle c of the first inclined surface and an inclination angle d of the second inclined surface of a linear prism formed closest to the side end surfaces at which the light sources are disposed satisfy a relationship 2×c<e1?e2<d/2.

Abstract: A side-light type spread illuminating apparatus includes a light guiding plate; a light source arranged along a light entering face of the light guiding plate; a double-sided prism sheet arranged at a light emitted face side of the light guiding plate; and an optical member arranged at a back face side facing the light emitted face of the light guiding plate. The optical member includes a light absorption member allowing prevention of reflection of light that has been introduced into the optical member.

Abstract: An apparatus includes a two-sided prism sheet, and an optical path conversion unit with linear prisms. Each apex angle of the prisms increases the closer the linear prism is formed to the center in the light guide direction, and when a pair of inclined surfaces of each of the prisms has a first inclined surface and a second inclined surface, an inclination angle of the second inclined surface is larger than the one of the first inclined surface. Among the prisms, inclination angles e1 and e2 of a pair of inclined surfaces of a linear prism formed closest to the center and an inclination angle c of the first inclined surface and an inclination angle d of the second inclined surface of a linear prism formed closest to the side end surfaces at which the light sources are disposed satisfy a relationship 2×c<e1?e2<d/2.

Abstract: A side-light type spread illuminating apparatus includes a light guiding plate; a light source arranged along a light entering face of the light guiding plate; a double-sided prism sheet arranged at a light emitted face side of the light guiding plate; and an optical member arranged at a back face side facing the light emitted face of the light guiding plate. The optical member includes a light absorption member allowing prevention of reflection of light that has been introduced into the optical member.