Patent ID: 9417372
Filing Date: 2016-08-16
CPC Classification: G02B,G02F

Claim Text:
1. A lighting unit for a display device comprising: a plurality of light sources which emits light; a wedge-shaped light guide having an incident surface disposed close to the light sources and an opposing surface disposed opposite the incident surface; an optical sheet disposed on the light guide; and a lens sheet disposed on the optical sheet and spaced apart from the light guide, wherein the lens sheet comprises a plurality of lenses, each having an axis in a direction from the incident surface to the opposing surface, wherein, the light guide is thinner in height at the incident surface than at the opposing surface, a radius of curvature of each of the lenses adjacent to the incident surface is larger than the radius of curvature thereof adjacent to the opposing surface, and the radius of curvature (R) of a portion of a lens of the lenses satisfies the following equation: wherein n denotes refractive index of the lens of the lenses, M denotes a magnification ratio of the lens, y denotes a position of the portion on the axis of the lens, and ‘a’ and ‘b’ denote constants determined based on a structure of the light guide, and wherein a moving distance (H) of light from a corresponding light source of the light sources to the portion of the lens is given by ‘ay+b’.