Back to results
US 7,452,118 B2Granted
Area light source
AssigneeToshiba Matsushita Display Technology Co., Ltd.
InventorKenshi Tsuchiya
Life of this patent
Estimating the term…
Abstract
Area light source 10 used for LCD device 1 includes light guide 12 and LED devices 18 and 19 disposed at a side portion of light guide 12. A light receiving portion at a side edge portion of light guide 12 is provided with prisms 24 and 25 of saw-tooth prism group 22. Apex angles of prisms 24 and 25 are set to be more acute up to the middle point of prisms 24 and 25 as prisms 24 and 25 are farther from LED devices 18 and 19, respectively.
Claims8
An area light source comprising:
- a light guide having a plurality of light receiving portions, each of the light receiving portions being arranged side-by-side along a longitudinal direction, a prism group arranged at an irradiation area of each of the light receiving portions, the prism group including a plurality of prisms, each of the prisms being arranged side-by-side along the longitudinal direction;
- and
- a plurality of light emitting diode devices, each of the light emitting diode devices being arranged so that an optical center axis of each the light emitting diode device corresponds to a center axis of each of the irradiation areas, the light emitting diode devices facing the irradiation areas at a predetermined distance,
- wherein an apex angle of each of the prisms in the prism group changes symmetrically to the center axis, in both directions away from the center axis, along the longitudinal direction of the irradiation area.
1 more element
Dependencies are inferred from the claim text.