Front illumination device mounted between an illuminated object and a viewer and a reflection-type liquid crystal display device incorporating same
AssigneeSharp Kabushiki Kaisha
InventorYutaka Sawayama
Life of this patent
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Abstract
A front-light system for mounting on the front of a reflection-type LCD, etc., which serves as auxiliary illumination when surrounding light is insufficient, is provided with a wedge-shaped light-conducting body having a light-entry surface through which light enters from a light source, and an anisotropic light-scattering plate, which scatters light projected from an interface of the light-conducting body, so that light projected toward a liquid crystal cell is projected at an angle close to perpendicular with respect to the surface of the liquid crystal cell.
Claims29
A front illumination device comprising a light source and a light-conducting body which guides light from said light source to an object to be illuminated, said front illumination device to be used by mounting in front of said illuminated object, wherein:
- said light-conducting body includes a first light-conducting body provided with a light-entry surface, through which light from said light source enters, and a second light-conducting body provided with a light exit surface, through which light exits toward said illuminated object;
- said first light-conducting body guides light from said light-entry surface to said second light-conducting body;
- said second light-conducting body is provided so that light exiting therefrom exits in a direction closer to a normal direction of said light exit surface of said second light-conducting body than a direction in which light, guided by said first light-conducting body from said light-entry surface toward said second light-conducting body, strikes said light exit surface of said first light-conducting body;
- and
- said second light-conducting body is a light-scattering body, which scatters light.
A front illumination device comprising a light source and a light-conducting body which guides light from said light source to an object to be illuminated, and front illumination device to be used by mounting in front of said illuminated object, wherein:
- said light-conducting body includes a first light-conducting body provided with a light-entry surface, through which light from said light source enters, and a second light-conducting body provided with a light exit surface, through which light exits toward said illuminated object, said second light-conducting body being deposited on a side of said first light-conducting body opposite to said illuminated object;
- said first light-conducting body guides light from said light-entry surface to said second light-conducting body;
- said second light-conducting body is provided so that light exiting therefrom exits in a direction closer to a normal direction of said light exit surface than a direction in which light exits from said first light-conducting body;
- and
- said second light-conducting body is a light-scattering body, which scatters light.
A front illumination device comprising a light source and a light-conducting body which guides light from said light source to an object to be illuminated, said front illumination device to be used by mounting in front of said illuminated object, wherein:
- said light-conducting body includes a first light-conducting body provided with a light-entry surface, through which light from said light source enters, and a second light-conducting body provided with a light exit surface, through which light exits toward said illuminated object;
- said first light-conducting body guides light from said light-entry surface to said second light-conducting body;
- said second light-conducting body is provided so that light exiting therefrom exits in a direction closer to a normal direction of said light exit surface of said second light-conducting body than a direction in which light, guided by said first light-conducting body from said light-entry surface toward said second light-conducting body, strikes said light exit surface of said first light-conducting body;
- and
- said second light-conducting body is a diffraction element, which diffracts light.
Dependencies are inferred from the claim text.