Patent ID: 7040796
Filing Date: 2006-05-09
Classification: G02B,G02F

Abstract:
1. An illumination device comprising: a light guide plate; an intermediate light guide disposed along one side face of the light guide plate; and a light emitting element disposed at an end face in a lengthwise direction of the intermediate light guide, wherein the side face of the light guide plate serves as a light incident face from which light is introduced, light emitted from the light emitting element is introduced into the light guide plate through the intermediate light guide and the light incident face, and the light propagating inside the light guide plate is emitted from one surface of the light guide plate, wherein the intermediate light guide protrudes from the light guide plate in a direction along the light incident face of the light guide plate toward the light emitting element, a side face of the intermediate light guide opposing the side face of the light guide plate serves as an emergent face from which the light from the light emitting element emerges toward the light guide plate, and an outer side face of the intermediate light guide remote from the emergent face serves as a reflecting face for reflecting the light propagating inside the intermediate light guide, wherein the outer side face of the intermediate light guide is provided with at least one of a plurality of grooves of wedge-shaped cross section or a plurality of minute irregularities provided distant from the end face of the intermediate light guide, and a reflective film formed on the at least one of grooves or irregularities, and wherein the at least one of grooves or irregularities on the outer side face of the intermediate light guide extend from a position at a distance within the range of −1 mm to +0.5 mm from an extension line of an end face of the light guide plate close to the light emitting element, the extension line reaching the outer side face of the intermediate light guide, when the symbol “−” indicates a side offset from the extension line toward the light emitting element, and the symbol “+” indicates a side offset from the extension line away from the light emitting element.