초록 ▼

Light is supplied into a light incident surface 2 from a fluorescent lamp L enclosed by a silver foil sheet R, and parallelized illuminating light flux is taken out from a light exit surface 3. On a back surface 4 side of a light flux parallelizer 1, across or without a thin air layer 5, a polarizat

Light is supplied into a light incident surface 2 from a fluorescent lamp L enclosed by a silver foil sheet R, and parallelized illuminating light flux is taken out from a light exit surface 3. On a back surface 4 side of a light flux parallelizer 1, across or without a thin air layer 5, a polarization converter .EPSILON. is disposed. The polarization converter .EPSILON. reinforces the polarization function of the surface light source device through polarization conversion action accompanying reflection in the prism. At a position confronting the light exit surface 3 across an air layer 7, a polarization separating plate 8 is disposed. At a further outside, across an air layer 9, an exit light direction modifier 10 is disposed. A bright polarized illuminating light flux is emitted from a light exit surface 11. When applied to a backlight of a liquid crystal display, a liquid crystal display panel is disposed at a further outside of the exit light direction modifier 10.

대표청구항 ▼

[ What is claimed is:] [1.] A surface light source device with polarization function comprising:a light flux parallelizer composed of a plate form light scattering light guide having a wedge shaped section, and light feed means disposed at the thicker end side of the light flux parallelizer, andligh

[ What is claimed is:] [1.] A surface light source device with polarization function comprising:a light flux parallelizer composed of a plate form light scattering light guide having a wedge shaped section, and light feed means disposed at the thicker end side of the light flux parallelizer, andlight permeable polarization separating means having reflection characteristic depending on polarization components, being disposed so as to extend along the light exit surface of the light flux parallelizer,wherein the polarization separating means comprises a polarization separating plate having a refractive index in a range of 1.3 to 2.0, and a repetitive slope for approximately satisfying the Brewster's angle condition for the exit direction of the parallel light flux emitted from the light exit surface of the light flux parallelizer is formed on the light incident surface of the polarization separating plate.