Light control sheet, surface light source device and liquid crystal display
AssigneeEnplas Corporation
InventorShingo Ohkawa
Life of this patent
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Abstract
A light control sheet suitable for direction-controlling an angularly extending oblique input light, surface light source device and LCD using the light control sheet. A light control sheet is disposed along an emission face of a light guide plate direction-controls main and subsidiary light fluxes to cause them to be emitted toward a desired direction. Main beam S1 emitted from the emission face transmits (with a small refraction) through a first face, being inner-reflected (total reflection) by a first slope region and then outputted from a light output face (SS1). First subsidiary beam T1 transmits (with a small refraction) through the first face, being inner-reflected (total reflection) by a second slope region and then outputted from the light output face (TT1).
Claims9
A light control sheet having a face to provide a light input face and another face to provide a light output face, said light input face being provided with a great number of projection rows running in parallel with each other,
- wherein each of said great number of projection rows includes a first face and a second face,
- said second face being inclined with respect to a frontal direction of said light output face of said light control sheet and having a variation in inclination angle such that the inclination angle gets smaller with a decreasing distance from said light output face,
- said first face being formed so as to introduce an input light containing both a main light beam, which travels in a direction inclined with respect to said frontal direction, and a first subsidiary light beam, which travels in a direction angularly nearer to said frontal direction before being introduced to said first face as compared with said main light beam, and further as to then cause said input light to be incident to said second face.
A surface light source device comprising a light guide plate, a primary light source to supply light to said light guide plate from an end portion of said light guide plate and a light control sheet disposed along an emission face provided by a major face of said light guide plate, said light control sheet having a face to provide a light input face and another face to provide a light output face, said light input face being provided with a great number of projection rows running in parallel with each other,
- wherein each of said great number of projection rows includes a first face and a second face,
- said second face being inclined with respect to a frontal direction of said light output face of said light control sheet and having a variation in inclination angle such that the inclination angle gets smaller with a decreasing distance from said light output face,
- said first face being formed so as to introduce an input light containing both a main light beam, which travels in a direction inclined with respect to said frontal direction, and a first subsidiary light beam, which travels in a direction angularly closer to said frontal direction before being introduced to said first face as compared with said main light beam, and further as to then cause said input light to be incident to said second face.
A liquid crystal display including a liquid crystal display panel and a surface light source device illuminating said liquid crystal display panel,
- said surface light source device comprising a light guide plate, a primary light source to supply light to said light guide plate from an end portion of said light guide plate and a light control sheet disposed along an emission face provided by a major face of said light guide plate, said light control sheet having a face to provide a light input face and another face to provide a light output face, said light input face being provided with a great number of projection rows running in parallel with each other,
- wherein each of said great number of projection rows includes a first face and a second face,
- said second face being inclined with respect to a frontal direction of said light output face of said light control sheet and having a variation in inclination angle such that the inclination angle gets smaller with a decreasing distance from said light output face,
- said first face being formed so as to introduce an input light containing both a main light beam, which travels in a direction inclined with respect to said frontal direction, and a first subsidiary light beam, which travels in a direction angularly closer to said frontal direction before being introduced to said first face as compared with said main light beam, and further as to then cause said input light to be incident to said second face.
Dependencies are inferred from the claim text.